2009 NORTHEASTERN NATURALIST 16(Monograph 3):1–88
Nesting Behavior of the Tachysphex terminatus Species
Group (Hymenoptera: Crabronidae)
Frank E. Kurczewski*
Abstract - The nesting behavior of species in the Tachysphex terminatus group is
presented in phylogenetic order following Pulawski (1988). Eight taxa are treated:
T. clarconis, T. antillarum, T. alpestris, T. linsleyi, T. terminatus, T. similis, T. a. apicalis,
and T. apicalis fusus. This paper includes a literature review summary for each
species, Howard E. Evans’ unpublished field notes on T. linsleyi, T. terminatus, and
T. similis, unreported insect museum prey records for T. terminatus and T. apicalis
fusus, and long-term field studies on T. terminatus, T. similis, T. a. apicalis, and T.
apicalis fusus. The field observations were made during the years 1960–2005 and
include 929 nests excavated and examined at 52 locations in the central and eastern
United States and southern Ontario. Emphasis is placed on: burrow excavation,
tumulus leveling, temporary closure, orientation flight, hunting, prey capture, prey
transport, nest entry, final closure, burrow design and length, cell depth, cell shape
and size, number of cells per nest, cell sequential position, number of prey per cell,
prey and wasp weights, total prey biomass per cell, position of prey in cell, and placement
of wasp’s egg on prey.
Introduction
Tachysphex is a very large genus of ground-nesting solitary wasps, with
444 species worldwide (Pulawski 2008). Eighty-three species inhabit North
America, Central America, and the Caribbean Region (Pulawski 1988). The
majority of nearctic species is found in the western United States and northern
Mexico in habitats with high temperature and low humidity (Pulawski
1988). Many of the species have two or more generations per year in the
Austral and Tropical regions.
Species of Tachysphex are largely cursorial and fast moving (Williams
1914), as the genus name implies (tachys = swift, sphex = wasp). The North
American species excavate mainly short burrows and shallow cells in sandy,
gravelly or, rarely, loamy soils. They store the cells with paralyzed orthopteroid
insects, primarily nymphal grasshoppers (Acrididae) (Krombein
1979, Pulawski 1988).
The Tachysphex terminatus species group is restricted to the New World,
ranging from Alaska to Argentina (Pulawski 1988). Seven of the 11 species
in the group are found in the United States: T. clarconis Viereck, T. ruficaudis
(Taschenberg), T. alpestris Rohwer, T. linsleyi R. Bohart, T. terminatus (F.
Smith), T. similis Rohwer, and T. apicalis W. Fox (Pulawski 1988). There are
four extralimital species: T. antillarum Pulawski and T. quisqueyus Pulawski
(West Indies), T. galapagensis Rohwer (Galapagos Islands), and T. peruanus
Pulawski (Peru).
*PO Box 15251, Syracuse, NY 13215; Fkurczewski@twcny.rr.com.
2 Northeastern Naturalist Vol. 16, Monograph 3
Species in the group are characterized morphologically by the presence
of convexities behind the posterior ocelli (Bohart 1962, Pulawski 1988,
Williams 1914), wide vertex (space between compound eyes at top of head;
Fox 1894, Pulawski 1988), mainly long erect setae on the vertex (Pulawski
1988, Williams 1914), and unmodified apical tarsal segments
(Pulawski 1988). Males and females resemble one another in size and coloration.
Members of the species group are rather small in size (3.5–10.0
mm long) and often black with a red abdominal tip, hence the species
names ruficaudis, terminatus, and apicalis. Intraspecific variation often includes
abdominal coloration and wing infuscation (Pulawski 1988). More
red on the abdomen and hyaline wings are characteristic of arid regions;
black individuals with more infuscated wings are found in areas of higher
relative humidity, cooler temperatures, and higher elevation.
Species in the terminatus group have two or more generations per year
throughout much of their range. They nest mostly in level or slightly sloping,
barren or sparsely vegetated sandy soil. However, T. apicalis nests in
sand cliffs and strongly sloping sandbanks (Kurczewski and Snyder 1968).
Nesting behavior is characterized by several group-specific components.
Except for T. apicalis, females spend much time on the sand surface leveling
the soil removed during burrow excavation. After completing the
burrow, they temporarily close the nest entrance with sand and then make an
orientation flight above the area before searching for prey. The mostly small,
prey grasshoppers are transported to the nest, usually in flight, and released
headfirst in front of the entrance, followed by removal of the temporary sand
closure, nest entry, exit, and re-entry with prey. In T. apicalis, leveling the
sand and making and removing the temporary closure of the entrance are absent
due to the limitations of the sand cliffs and strongly sloping sandbanks.
The method of final closure in this species is group-atypical in accord with
its unusual habitat (Kurczewski and Snyder 1968). Under optimal nesting
conditions, a finished nest often contains two to five cells, with several or
many paralyzed prey placed in each cell. The wasp’s egg is laid transversely
across the pro- and mesosterna of a grasshopper, being affixed by the less tapered,
distal end to the soft intersegmental membrane surrounding the base
of a forecoxa.
The terminatus group contains both sympatric (T. terminatus, T. similis)
and allopatric (T. terminatus, T. alpestris; T. apicalis fusus, T. a. apicalis)
forms with broad ranges, and relatively isolated forms (T. antillarum, T.
quisqueyus) restricted to the West Indies. The specializations that enable the
sympatric species to co-exist, often side-by-side in mixed aggregations, and
those that restrict the isolated allopatric populations to particular geographic
areas present interesting evolutionary phenomena for study. Although the
morphological distinctions are sometimes subtle, ecological and behavioral
differences offer reliable taxonomic characters for some of the species. Species
of Tachysphex are a rewarding group for study because of their varied
nesting behavior (Bohart and Menke 1976).
2009 F.E. Kurczewski 3
The purpose of this paper is (1) describe, categorize, and analyze the
nesting behavior of species in the terminatus group, paying particular attention
to species-specific components; (2) compare species behavior patterns
in order to find similarities, contrasts, omissions, and additions; and (3)
correlate species differences with pertinent morphological characteristics
to make possible a functional interpretation of what would otherwise be
obscure structural features.
Methods
This paper is an attempt to assimilate all pertinent information on the
nesting behavior of species in the Tachysphex terminatus group. Such information
is presented by species in phylogenetic order following Pulawski
(1988): T. clarconis, T. antillarum, T. alpestris, T. linsleyi, T. terminatus,
T. similis, T. a. apicalis, and T. apicalis fusus (Fig. 1). A specific order of
information is presented under each species. First, the known literature
on species’ nesting behavior is reviewed. Second, Howard E. Evans’ unpublished
notes on T. linsleyi, T. terminatus, and T. similis are detailed.
Third, previously unreported prey records from several insect museums are
presented. Fourth, long-term field studies on T. terminatus, T. similis, T. a.
apicalis, and T. apicalis fusus are described, categorized, and analyzed.
Aggregations of T. terminatus, T. similis, T. a. apicalis, and T. apicalis
fusus were located with the aid of state/province soil association maps,
United States Department of Agriculture soil surveys, aerial photographs,
and state road maps. The aerial photographs were especially useful in locating
sizeable areas of bare sand and gravel such as abandoned and active
sandpits, gravel pits, sandbanks, and sandblows.
Figure 1. Hypothetical phylogenetic tree of species in Tachysphex terminatus group
based mainly on external morphological characteristics (after Pulawski 1988).
4 Northeastern Naturalist Vol. 16, Monograph 3
Nine hundred twenty-nine nests were excavated and examined at 52
sites in the central and eastern United States and southern Ontario during
the years 1960–2005. Site location, site description, site code number, and
inclusive date(s) of observation are given for T. terminatus and T. similis in
Tables 1 and 7, respectively. Site code numbers, descriptions, locations, and
inclusive date(s) of observation for other species are included in the text.
Site code number (TX-number) associates field notes with specimens and
identifies the species of wasp and prey, site location, and date(s) of observation
and collection. At least one female or male was collected from each site
to serve as a voucher specimen. The specimens have been deposited in the
Cornell University insect collection.
Soil samples from nesting sites in New York (TX-1, 2, 20, 36, 76, 94),
Kansas (TX-54, 56, 63, 67), and Florida (TX-4, 7) were analyzed at the State
University of New York College of Environmental Science and Forestry,
Syracuse, NY. Samples were screened to separate fine gravel, coarse sand,
medium sand, fine sand, and silt/clay using the United States Department of
Agriculture mm scale. Samples were sorted into particle size, weighed, and
percent sample weight calculated. Soil color, hue, and value/chroma were
delineated by comparison with the Munsell soil color chart.
Emergence data on first and last generation T. terminatus (TX-56, 54,
respectively) and first generation T. similis (TX-67) were obtained through
direct observation of recently emerged individuals with full wings, complete
foretarsal digging rakes, and clean integument. Recently emerged first-generation
females of both species were hand netted, frozen, examined under
a microscope for specific determination, and weighed (wet) on a Mettler
balance. Tachysphex similis included both all-black and red abdominal apex
variants. The weights of captured individuals were plotted against dates of
emergence to determine if there was a size-emergence date correlation.
Some live females were hand-netted, marked on their scuta with nontoxic
paint, released at the site, and followed. Nests were marked with
colored toothpicks that were dated and numbered chronologically. The
wasps accepted the presence of the toothpicks and often used them for
orientation. Nest density involved measuring the distance between adjacent
nest entrances.
Nesting aggregations were observed daily from 0800–0900 to 1700–1830
hours (Eastern or Central Daylight or Standard Time), weather permitting.
Type of wasp activity was noted, described, and quantified. Some behavioral
components were photographed in the field. Emphasis was placed on burrow
excavation, tumulus leveling, temporary closure of the entrance, orientation
flight, hunting, prey capture and transport, nest entry, and final closure.
Wasps flying to and from nests were timed with a stopwatch between consecutive
provisioning trips and from entry to exit.
Tachysphex terminatus females in New York (TX-1, 20, 36 [34 individuals])
and Kansas (TX-54, 56 [28]) and T. similis females in Kansas (TX-55,
61, 63, 66, 67 [10]) and Florida (TX-4, 7 [16]) were marked, observed, and
2009 F.E. Kurczewski 5
their activities measured during provisioning sequences. Time intervals between
consecutive prey items and duration to open temporary closure, turn
around inside the burrow and reappear in the entrance, place prey in the cell,
and temporarily close the nest entrance with sand were recorded using a stop
watch. Time of day, temperature in degrees centigrade, and cloud cover were
recorded concurrently with these data.
Tachysphex similis and T. terminatus differed in their rates of activity
at the same temperature. Two behavioral components selected for study
exemplified this difference: (1) temporary closure of the entrance and (2)
removal of the closure prior to nest entry. Wasps were timed with a stopwatch
as they temporarily closed their entrances with sand and, later, when
they returned with prey and removed the sand fill. Sand surface temperatures
were simultaneously recorded from unshielded, narrow-range (range
= 8 ºC), high-temperature mercury thermometers (ASTM RICCO) placed
beside entrances. Both behaviors were examined over the range of sand
surface temperatures at which these species nested (29–63 °C and 28–65 °C,
respectively). The data were erratic and curvilinear below 35 ºC. Therefore,
only measurements from 35° to 60 ºC were used for ease in comparison and
analysis. An attempt was made to obtain at least 20 measurements for each
species in each region for every degree centigrade in the 35–60 °C range.
Tachysphex terminatus was studied in New York and Kansas and T. similis
was examined in Florida and Kansas to account for geographic variation.
Seven of the sites selected for comparison were chosen based upon equivalent
soil texture values (Tables 2 and 6). For example, both TX-1 and TX-54
had >80% fine gravel and coarse sand, TX-36 and TX-56 had >70% coarse
sand and medium sand, and TX-7 and TX-67 had approximately 70% fine
gravel and coarse sand.
The lower sand surface temperatures were obtained in the morning as
the sun was rising to an overhead position. The higher sand surface temperatures
were obtained mainly between noon and mid-afternoon when the
sun was at zenith or just beyond zenith. No temperatures were recorded after
mid-afternoon when the sun was declining and the sand was gradually and
steadily cooling. The time lag between the thermometer temperature and the
sand surface temperature would have introduced an error of 1–2 ºC under
late afternoon conditions.
Burrows and cells were excavated, examined, measured, and drawn. Burrow
design and length, number of cells per nest, cell orientation and sequential
position, cell depth, cell shape and size, number of prey per fully provisioned
cell, position of prey in cell, and placement of wasp’s egg on prey were recorded
in the field. Prey were removed from the cells, put in individual vials
according to nest number, placed on ice in a cooler, transported to a laboratory,
and weighed (wet) on a Mettler balance. The aggregate prey weight
of each cell was summed. The grasshoppers were then transferred to vials
with glycerol, code-labeled, and sorted to subfamily. The majority of prey
was sent to US Department of Agriculture and National Museum of Natural
6 Northeastern Naturalist Vol. 16, Monograph 3
History orthopterists for identification. The wasps were placed in individual
vials, put on ice, transported to a laboratory, weighed (wet), frozen, pinned,
and code-labeled. The wasp species were tentatively identified by the author
(F. Kurczewski) and, later, the identifications verified by one of three hymenopterists.
Live wasp eggs were removed from the pedestal prey in the field
and measured using a binocular microscope with an ocular micrometer.
The contents of five fully provisioned cells in Kansas (TX-54) and 10
fully provisioned cells in New York (TX-1) were removed from an excavation,
placed in individual rearing tins, and observed on a daily basis until adult
emergence. Larval development and growth, beginning of cocoon construction,
cocoon completion, and adult emergence were observed and recorded.
Two-sample t-tests using independent samples were computed to
compare means for the following T. similis and T. terminatus data: wasp generation
and time spent between consecutive prey items; wasp generation and
individual prey, aggregate prey per cell, and wasp weights; T. similis Florida
and Kansas wasp weights; oviposition prey and other prey in cell weights; T.
terminatus and T. similis all sites temporary closure and removal of sand fill
duration; and T. terminatus and T. similis Kansas sites temporary closure and
removal of sand fill duration. Least-squares regression line, Pearson’s linear
correlation coefficient (r), and/or coefficient of determination (R2) were
computed for the following T. similis and T. terminatus data: emergence
date and wasp weight, and wasp weight and cell depth, T. similis Florida and
Kansas wasp weight and cell depth, and mean duration of temporary closure
and temporary closure removal. Statistical significance for all tests was assumed
when P < 0.05. Bar graphs and standard error bars were computed
for mean sand removal interval, mean sand removal distance, mean duration
spent distributing sand, mean sand retrieval duration, mean sand retrieval
distance, and mean sand retrieval interval for T. similis and T. terminatus.
Tachysphex clarconis
Literature review
Evans (1970) reported on the nesting behavior of this species as T.
sp. near linsleyi, later corrected to T. clarconis (Kurczewski and Evans
1986). Evans discovered two probably unfinished nests at Jackson Hole,
WY. One nest had two cells “side by side,” about 1 cm apart, at a depth
of 5 cm. One cell contained four “very small” grasshoppers and the other
cell held five prey. The wasp’s egg was laid on the prosternum of a grasshopper
transversely behind the front coxae. The grasshoppers, identified
as early instars of Melanoplus sp., were “considerably smaller” than the
“small” wasp and measured only 4 mm in body length. A small, immature
Melanoplus sp. was collected later with a second wasp.
A third female was observed flying with prey to her nest, holding the
grasshopper with her mandibles and legs. She released it near the entrance,
removed the temporary closure, entered the burrow, reappeared in the opening,
and pulled in the grasshopper “by its antennae.” This nest had only one
2009 F.E. Kurczewski 7
cell at a depth of 3.5 cm. The cell held three immature grasshoppers, probably
Chloealtis conspersa (Harris) (Acrididae), 6–8 mm long. The cell was
likely unfinished as no mention of the wasp’s egg was made.
Elliott and Kurczewski (1985) noted four females of T. clarconis nesting
in sand at St. Anthony, Fremont County, ID. One female made 40 entries to
remove soil from her burrow during excavation. An unidentified miltogrammine
fly attended the excavating wasp. The amount of time the wasp spent
between consecutive entries and exits onto the surface to level the removed
sand increased from start to finish. After 44 min of excavation, the female
made hovering flights above the area, flew off to rest on vegetation, returned,
and temporarily closed the entrance with sand. Prey grasshoppers were then
carried consecutively in extended flights directly to the nest and deposited
near the entrance. One “rather large” grasshopper was brought to the nest in
a series of short flights. With each prey, the female removed the sand closure,
entered the burrow, reappeared headfirst, and pulled in the grasshopper by its
antennae. Three cells contained three to six grasshoppers identified as Melanoplus
sanguinipes (Fabricius) (8 examples) and M. foedus Scudder (1). A
Hedychridium sp. (Chrysididae), a probable cleptoparasite on Tachysphex
wasps, dug into one nest while the wasp was away.
Tachysphex antillarum
Literature review
Tachysphex antillarum was observed nesting at four locations in Cuba
(Genaro and Sanchez 1992). All sites consisted of bare friable soil, the largest
area being 106.5 x 33 m. The soil selected for nesting ranged from “pure
fine sand” to “black, scarcely friable soil.” Although nesting in bare ground,
most nests were dug beside stones. This species was multivoltine and nested
throughout the year.
Females always leveled the soil removed from burrow excavation. After
finishing a burrow, the wasp temporarily closed the entrance with soil.
Prey grasshoppers were transported to the nest in flight, being held with
the wasp’s mandibles and legs. The prey was released about 1 cm from the
entrance in a ventral side upward position after which the wasp removed
the temporary closure, entered, reappeared in the opening, and pulled in the
grasshopper by the antennae or, rarely, a leg.
Nests contained up to five cells. Burrow length averaged 5.9 ± 1.04 cm
(range = 4.5–8.5, n = 28). Cell depth averaged 2.3 ± 1.14 cm (range = 1.0–5.2,
n = 28). Six to 11 grasshoppers (mean = 8.2 ± 1.86, n = 20 cells) were placed in
the cells head inward and often ventral side upward. Prey averaged 4.9 ± 1.15
mm (range = 3.0–9.0, n = 208) in body length. The nymphal grasshoppers were
identified as Parachloebata (= Orphulella) scudderi Bolivar (148 examples),
Chortophaga cubensis Saussure (35), and an unidentifiable species (22). The
wasp’s egg was placed on the innermost prey in the cell, usually one of the
largest individuals, and affixed in the genus-typical position. Wasp cocoons
averaged 7.2 ± 0.70 mm (range = 6.0–8.1, n = 21) in length.
8 Northeastern Naturalist Vol. 16, Monograph 3
More than half the cells (53.6%) were infested by maggots or puparia of
two species of miltogrammine flies, Senotainia (= Sphixapata) rubriventris
(Macquart) and Senotainia (= Sphixapata) trilineata (Van der Wulp). Some
provisioning wasps altered their flight patterns or did not enter their nests
upon the presence of such flies. Some females flew at the flies in an attempt
to drive them away. Wasps often inspected prey with their antennae and
mouthparts following fly intervention.
Tachysphex alpestris
Literature review
The taxonomic status of T. alpestris is currently in question. Elliott
and Kurczewski (1975) treated the taxon as a western population of T.
terminatus. Pulawski (1988) elevated the form to specific status, although
he indicated that it might be a geographical race of T. terminatus.
Buck (2004), after analysis of specimens where the two taxa intergrade
on Manitoulin Island, ON, Canada, believed that T. alpestris is merely a
subspecies of T. terminatus. Regardless of its status, the species or subspecies
is an inhabitant of psammophilous sites. Buck (2004) reported it from
sandy areas, sand dunes, dunes, dune trail, beach, sandy forest edge, old
sandpit, and sandy field.
Evans (1970) observed T. alpestris, identified initially as T. terminatus
(Kurczewski and Evans 1986), nesting at Jackson Hole, WY. He reported
this species making a temporary closure of the nest entrance, excavating
one- and three-celled nests, preying on small acridid nymphs, and stocking
several prey per cell. Cell depths were 3.2 cm for the one-celled nest and
4.0–4.5 cm for the three-celled nest. The wasp’s egg was placed on a prey
in a cell in the position typical of the genus. Twenty prey grasshoppers from
the nests were all identified as immature Chorthippus curtipennis (Harris)
(Acrididae), 5–9 mm (mean = 6.5) long.
F.E. Kurczewski, using Evans’ field notes, added that prey transport was
by flying and the three-celled nest contained three (no egg), two (egg), and
13 (egg) prey per cell (Kurczewski and Evans 1986). Burrow lengths were 5
cm for the one-celled nest and 8–10 cm for the three-celled nest (Kurczewski
and Evans 1986).
Elliott and Kurczewski (1985) noted a female from Morro Bay, San
Luis Obispo County, CA pinned with a nymphal acridid, Oedaleonotus
sp. Pulawski (1988) reported three females pinned with prey Acrididae:
(1) no locality label (actually the wasp, 8.5 mm long and determined as T.
terminatus by F.E. Kurczewski, was from Santa Cruz, Santa Cruz County,
CA), “two young nymphs” of Melanoplus sp., 7.0 and 8.5 mm long; (2)
Sierra Valley, CA, “four young nymphs” of Melanoplus sp., probably sanguinipes;
and (3) Arcata area, Humboldt County, CA, nymphal Microtes
sp., probably helferi (Strohecker).
2009 F.E. Kurczewski 9
Tachysphex linsleyi
Literature review
Krombein (1967) recorded unidentified acridid nymphs as prey of this species.
A female from Rodeo, Hidalgo County, NM is pinned with an immature
Eremiacris (= Paropomala) pallida (Bruner)(Acrididae)(Pulawski 1988).
H.E. Evans’ field note
H.E. Evans’ field note no. 1867 (1 mile w. Lajitas, Presidio County, TX;
April 28, 1963) refers to T. linsleyi (det. R.M. Bohart). The female, 7.0 mm
long, excavated a nest at 1000–1100 hours in “soft, powdery clay-sand” in
the side of a footprint. She temporarily closed the entrance at about 1100. By
1500, the wasp had entered, exited, and temporarily closed her nest several
times. At 1605, she entered her burrow without prey, exited, made a temporary
closure, and left. The female was observed making a final closure at
1715, coming out frequently and backing into the burrow while raking soil
backward. The rather straight burrow was 4 mm in diameter. It was 9 cm
long and led to a cell, 6 X 11 mm, at a depth of 6.5 cm including cell height.
There were seven acridids inside, with the wasp’s egg affixed near a front
leg of a grasshopper at the back of the cell. The immature grasshoppers were
identified as Psoloessa sp., possibly texana Scudder (Gomphocerinae) (6 examples,
4.5–6.5 mm long) and Clematodes larreae Scudder (Melanoplinae)
(one, 9.5 mm long).
Tachysphex terminatus
Literature review
Ashmead (1894) was the first to report on aspects of the nesting behavior
of T. terminatus. Citing C.V. Riley’s manuscript notes, he recorded this
species preying on the acridid Chortophaga viridifasciata (DeGeer). Rau
(1926) also found T. terminatus preying on C. viridifasciata.
Williams (1914) collected a female of this species in Kansas with a
“young tryxalid” (= Gomphocerinae). He noted another female nesting in
sand in Graham County, KS and making a temporary closure of the entrance.
The wasp later finally closed this nest, smoothed over the area, and took
flight. The short burrow led to a single, fully provisioned cell that contained
“several acridians of very small size.”
Rau and Rau (1918) found T. terminatus at two sites in/near St. Louis, St.
Louis County, MO. Females at the first site nested in sandy soil, those at the
second site in “clayey” soil. Wasps that dug in clayey soil made numerous
false starts, whereas those digging in sandy soil usually finished the excavation,
unless disturbed. In digging a burrow, the female flung sand backward
beneath her body with her forelegs. Periodically, she backed from the burrow
to rake away the accumulated sand in front of the entrance. After excavating
a burrow, the wasp closed the entrance with loose sand. She always filled the
entrance completely, although the closure was “loosely packed.” One female
made no orientation flight—presumably because she was already familiar
with her surroundings.
10 Northeastern Naturalist Vol. 16, Monograph 3
Rau and Rau (1918) noted that females with prey flew directly to their
nests, holding the grasshopper beneath the body. One wasp released her prey
on the sand, removed the temporary closure, went inside, turned around,
came out, and pulled in the grasshopper. She reappeared in the opening, remade
the closure, and flew away. After stocking the cell, the female filled the
burrow with loose sand and attempted to conceal the entrance by covering it.
A burrow in sandy soil comprised a short, curving channel “about three
inches long” terminating “about an inch and a half below the surface.” Rau
and Rau (1918) erroneously reported that there was no cell. Rau (1926)
noted that nests dug in loose dirt on the top of a “clay bank” were so shallow
that they could be readily exposed by a person blowing on them.
Five to nine prey were “usually used to provision a cell.” Rau and Rau
(1918) mentioned that one larva fed on the ventral side of the grasshopper
between the second and third pairs of legs. Prey included small and mediumsized
nymphs of Arphia sulphurea (Fabricius), Syrbula admirabilis (Uhler),
Dichromorpha viridis (Scudder), Melanoplus sp., and an unidentifed Oedipodinae
(Rau 1946, Rau and Rau 1918).
Strandtmann (1953) noted T. terminatus nesting in loose soil under a
farm implement shed near Maxwell, Caldwell County, TX. He believed
the wasps nested from May through October, allowing five generations of
wasps per year at the rate of one generation per month. Burrows sloped
evenly at about a 45° angle for 7–10 cm, ending in enlarged cells about 3
cm deep. “Two cells contained seven small hoppers each.” The number of
grasshoppers per cell “was inversely proportional to their size.” An “average
of four” grasshoppers per completed cell was his “conservative estimate.”
Grasshoppers removed from the cells comprised first and second instars of
Melanoplus and Tryxalus. Tryxalus is not a New World genus (Finnamore
1982). Strandtmann (1953) figured one wasp atop its prey in an atypical
dorsal side upward position.
Kurczewski (1966a) reported on the extremely rare use of bush katydids
(Tettigoniidae) as prey in three single-celled nests of T. terminatus in a
sandbank at Groton, Tompkins County, NY. The three cells each contained
a single tettigoniid along with two, five, and seven acridids (Melanoplus
bivittatus [Say]). A fourth bush katydid was abandoned on the sand surface
beside a nest entrance. This nest was later stocked entirely with nymphal
M. bivittatus. Wasps provisioning with bush katydids exhibited no atypical
prey transport or storage behavior. The wasps’ eggs were not laid on any of
the bush katydids, possibly because of their small sizes. Initially determined
as Phaneroptera by A.B. Gurney, the specimens were later re-identified by
D.A. Nickle as Scudderia sp., probably furcata Brunner von Wattenwyl
(Pulawski 1988).
Kurczewski and Harris (1968) noted 12 cells of T. terminatus in two 0.5-
m2 plots at the same site in Tompkins County, NY. They found T. terminatus
to be the second most abundant solitary wasp at the site in terms of nest
density, exceeded only by Oxybelus bipunctatus Olivier.
2009 F.E. Kurczewski 11
Kurczewski and Snyder (1968) summarized the nesting behavior of T.
terminatus in a paper on the evolution of cliff nesting in digger wasps. They
reported that a female excavated a shallow slanting burrow in sand, then
hunted and captured small grasshoppers of her own size or smaller that she
stored in an oval cell at the end of the burrow. When provisioning was finished,
the wasp laid an egg on one of the prey and sealed off the cell with
sand. Before filling the entire burrow with sand and making a new nest, she
commonly made and provisioned a second and third or even a fourth and
fifth cell at the ends of short side burrows leading from the main burrow.
The female closed the nest entrance with loose sand each time she went
afield to search for and capture a grasshopper. When she returned with prey
it was necessary for her to release the grasshopper on the sand near the entrance,
remove the sand fill, enter the burrow, turn around inside, come out,
and re-enter backward pulling the grasshopper in by its antennae. The prey
thus lay exposed on the sand for several seconds unprotected from the attacks
of satellite-flies. In the presence of the flies, a female sometimes raised
the legs of the grasshopper with her mandibles in an attempt to search for
fly maggots. One female nesting in a steep slope was relegated to making an
incomplete temporary closure. She entered her nest with a very small prey
directly without releasing the grasshopper on the sand.
Miller and Kurczewski (1973) reported on the speed at which T. terminatus
females opened and closed their nest entrances as sand surface
temperature increased. As temperature increased, the wasp dug more rapidly
and made and removed the temporary sand closure increasingly more
quickly. At 57 ºC, the female made several brief hovering flights to avoid
the hot sand surface. At 62 ºC, she made only a token effort to close the nest
upon leaving, thereby leaving the entrance partly open. Some, but not all,
females ceased provisioning during the hottest part of the day and remained
inside their burrows.
Spofford et al. (1986) reported on the cleptoparasitism of T. terminatus
eggs and larvae by three species of Miltogrammini (Diptera: Sarcophagidae)
in two sandy areas of central New York near Auburn, Cayuga County and near
Chittenango, Madison County. Phrosinella aurifacies Downes larviposited
primarily in temporarily closed entrances, the maggots burrowing through
the loose sand fill and down the burrow. Senotainia (= Sphixapata) vigilans
Allen maintained surveillance perches near wasp entrances and larviposited
on the prey while the female was preoccupied with provisioning activities.
Senotainia (= Sphixapata) trilineata was initially attracted by the wasp’s
provisioning flight and larviposited on the prey in mid-air or on the ground.
Females of T. terminatus attempted to prevent fly larviposition through
face-offs, chasing flights, and diversionary flights. Wasps also attempted to
remove maggots from the prey with their mandibles. Frequency of successful
cleptoparasitism at the two sites was 30.6% and 57.9%, respectively.
Spofford and Kurczewski (1990) documented the miltogrammine
fly cleptoparasites and frequency of cleptoparasitism of T. terminatus at
12 Northeastern Naturalist Vol. 16, Monograph 3
many sites in the eastern United States. Phrosinella aurifacies, Senotainia
(= Sphixapata) trilineata, and Senotainia (= Sphixapata) vigilans were the
predominant cleptoparasites of this wasp species. Spofford and Kurczewski
(1992) reported further on the species of Miltogrammini associated with
T. terminatus females and their nests, cataloguing several pre- and postlarvipositional,
counter-cleptoparasitic behavioral tactics employed by this
species in counteracting fly larviposition.
Kurczewski (2000) examined 2 three-celled and 3 two-celled nests of T.
terminatus in recently cleared nearly level sand in Brunswick County, NC.
The 12 cells were unearthed at depths of 27–48 mm (mean = 34.3) beneath
the surface, including cell height. The fully provisioned cells held three to
nine (mean = 6.4, n = 12) nymphal acridids identified as Melanoplus femurrubrum
(DeGeer) (46 examples), Dichromorpha viridis (3), Orphulella
pelidna (Burmeister) (24), and Dissosteira carolina (Linnaeus) (4). The individual
grasshoppers weighed (wet) 4–19 mg (mean = 11.3, n = 77). Two of
the wasps weighed 15 and 17 mg. Prey were placed in the cells head inward
and ventral or dorsal side upward or on the side. The wasps’ eggs were <2
mm long and affixed to the right (7) or left (5) forecoxal coria of the prey.
Females exited their overnight burrows in the morning to search for prey as
early as 0910 (EDT) at air and sand surface temperatures as low as 18 ºC and
25 ºC, respectively.
H.E. Evans’ field notes
H.E. Evans’ field note nos. 53, 56, 67, 76, 114, and 149 refer to field
studies of T. terminatus (det. R.M. Bohart) at 7 miles east of Manhattan and
Blackjack Creek, both sites in Pottawatomie County, KS. They include 5
one-celled nests. The 5 burrows entered the soil at 40–50° angles with the
surface and were 2–6 inches long. The cells were situated 1–3½ inches beneath
the surface, including cell height. They held 3–12 nymphal acridids (n
= 5). The largest prey was 13 mm long, but most others were less than 8 mm
long. The grasshoppers comprised Gomphocerinae and Melanoplinae, one
prey being identified as Melanoplus sp. Many of the grasshoppers were put
in cells head inward and ventral-side upward. A wasp’s egg, 2 mm long, was
laid at the base of a foreleg and extended transversely across the prothorax
between the fore- and midlegs.
The grasshoppers were carried in flight by the wasps, being held underneath
with the legs and mandibles. Each prey was released on the sand
surface as the female removed the temporary sand fill from her entrance.
The wasp then entered the burrow, came out, grasped the grasshopper by its
antennae, backed in with it, came out again, and refilled the entrance with
sand. Final closure involved the wasp raking sand backward into the burrow
as she backed inside.
Evans’ field note nos. 701, 1105, 1139, 1200, 1477, and 1554 pertain to
studies of T. terminatus (det. H.E. Evans) made in Oswego (Granby Center),
Tompkins (Six Mile Creek, SQR Sand Pit, Ithaca), and Wayne (Ontario)
counties, NY. The wasps’ burrows were 2–10 cm long with cells 1.5–6.5 cm
2009 F.E. Kurczewski 13
deep, including cell height. Three to seven nymphal acridids were placed in
five of the cells. The wasps’ eggs, 1.5–2.0 mm long, were attached as described
above. Prey transport and nest entry were as described above.
Evans’ field note nos. 1840, 1898, and 1900 refer to four nests of T. terminatus
(det. H.E. Evans) excavated and examined in a sandbank at Lexington,
Middlesex County, MA. The four burrows were 5.0–9.5 cm long, with cells
situated 3–5 cm beneath the surface, including cell height. The number of
prey per fully provisioned cell ranged from two to five. The grasshoppers
were identified as nymphs of Chloealtis conspersa (3 examples), Dissosteira
carolina (1), and Melanoplus sanguinipes (7). Nesting behavior and position
of the wasp’s egg on the grasshopper were as described above.
Insect museum specimens
A T. terminatus female, 8.0 mm long, in the Museum of Comparative
Zoology, Harvard University (H.E. Evans, Biol. note no. 1840) is associated
with two juvenile Dichromorpha viridis, 6.5 and 5.5 mm long, and one juvenile
Orphulella speciosa (Scudder), 9.5 mm long. Prey body lengths from
H.E. Evans’ Biological note nos. 1898 and 1900 specimens in the Museum of
Comparative Zoology were as follows: Chloealtis conspersa, 9.0, 8.0, 11.5
mm; Dissosteira carolina, 7.5 mm; and Melanoplus sanguinipes, 11.0, 7.5,
6.5, 11.0, 4.5, 6.0, 6.5 mm.
A female from Colorado (det. K.V. Krombein), 9.0 mm long, is pinned
with two juvenile Melanoplus sp., 9.0 and 8.5 mm long. A female T. terminatus
(det. K.V. Krombein) from Clifton, Prince William County, VA (“ex. 1
nest”) was collected with four juvenile Chortophaga viridifasciata, 9.5, 9.5,
7.5, and 9.5 mm long, and one juvenile Syrbula admirabilis, 7.5 mm long.
F.X. Williams collected four females from Boston, Suffolk County, MA (July
1913), 8.5–9.0 mm long, with two juvenile Melanoplus sp., 7.0 and 8.0 mm
long, one juvenile C. viridifasciata, 7.0 mm long, and one juvenile Arphia
sp., 7.5 mm long. Four females from Ithaca, NY, the oldest specimen being
dated August 10, 1886 (J.H. Comstock), 8.0–10.0 mm long, are pinned with
two juvenile Melanoplus femurrubrum, 8.0 and 8.5 mm long, one juvenile
Arphia xanthoptera (Burmeister), 8.0 mm long, and one juvenile genus unknown
(Acrididae), 7.5 mm long. A female from Hamilton, Madison County,
NY, 7.5 mm long, is pinned with a juvenile Melanoplus sp., 6.5 mm long.
A T. terminatus female from Barton County, KS, elevation 559 m (1816 ft.)
(June 22, 1912; F.X. Williams), 8.0 mm long, is pinned with a juvenile Mermiria
sp., 8.5 mm long. Two females from the Fridley Sand Dunes, Anoka
County, MN, 8.0 and 8.5 mm long, are pinned with a juvenile Melanoplus
sp., 8.5 mm long, and a juvenile Dichromorpha viridis, 9.0 mm long. A female
from a gravel pit at Forks of the Credit, Regional Municipality of Peel,
ON, Canada is pinned with a 4th-instar Chorthippus curtipennis (M. Buck,
University of Guelph, Guelph, ON, Canada, 2007 pers. comm.).
Field studies
Nest location. Tachysphex terminatus nested in bare or sparsely vegetated,
moderately dry, loose-to-firm fine gravel, sand, or loamy fine sand.
14 Northeastern Naturalist Vol. 16, Monograph 3
Nesting sites were usually level, but some sloped as much as 25–50° with
the horizon (Fig. 2). In some areas, the soil was loose and dry on the surface,
but moist, gravelly, or compact underneath. Most sites were surrounded or
bordered by vegetation—a necessity to provide a source of prey. Nests occupied
a variety of man-made or otherwise disturbed substrates (Table 1,
Fig. 2). Five rather large aggregations (TX-1, 20, 36, 54, 56) contained
Table 1. Tachysphex terminatus site code numbers, site locations, site descriptions, and inclusive
dates of observation.
Inclusive dates
Site No. Site location Site description of observation
TX-1 Groton, NY Sandbank 5 Aug–1 Sep 1960,
13 Jun–29 Aug 1961,
29 May–1 Aug 1962,
6 Jun–24 Jul 1963,
6 Jun–21 Jul 1964,
13 Jun 1967
TX-2 3 km E Auburn, NY Sandbank 16 Jun–29 Aug 1962,
18 Jun–23 Aug 1963
TX-10 Kill Devil Hills, NC Sand barren 23–24 Jul 1962
TX-19 2 km W Sennett, NY Sandy field 19 Jun–22 Jul 1963
TX-20 2 km S Auburn, NY Sandpit 22 Jun–23 Aug 1963,
11–28 Jul 1964,
23 Jun–6 Oct 1966,
14 Jun–15 Sep 1967,
7 Jul 1968
TX-24 Weymouth, NJ Sandy trail 29 Jun 1963
TX-26 Scullville, NJ Sandy field 30 Jun 1963
TX-27 Oyster Creek, NJ Sand pile 1 Jul 1963
TX-31 Five Points, NY Gravel pit 7–18 Jul 1963
TX-35 Cape May, NJ Sandy beach 16 Jul 1963
TX-36 Ithaca (Inlet Valley), NY Sandy field 4–9 Aug 1963,
12–26 Jul 1964,
9–29 Jun 1966
TX-38 Presque Isle State Park, PA Sandblow 27 Jul–17 Aug 1961,
26 Jul 1963,
3–10 Jul 1964
TX-41 Vincentown, NJ Sandy field 11–15 Aug 1963
TX-44 Colonie, NY Sand barren 17–18 Aug 1963
TX-48 Port Burwell, ON Sandy field 1 Jul 1964
TX-50 Lakeview, KS Sandy lakeside 21 Aug-14 Sep 1964,
13 May–4 Jul 1965
TX-54 6 km SE Lecompton, KS Sandy RR embankment 3 Sep 1964,
9 May–27 Oct 1965,
5–30 May 1966
TX-56 8 km NW Lawrence, KS Sand flats 22 May–13 Sep 1965,
5–30 May 1966
TX-60 8 km E Manhattan, KS Sandy draw 16 May–15 Aug 1965
TX-69 4 km N Guthrie, OK Sand flats 12 Aug 1965
TX-86 2 km SE Erie, PA Gravel pit 2 Jul–29 Aug 1983
TX-95 Allegan State Game Area, MI Sandy trail 11–13 Jun 1993
TX-97 Canadian Forces Base Borden, ON Sandy trail 27 Jul 1996
TX-99 Cape Henlopen State Park, DE Sandy parking lot 11–13 Jun 2005
2009 F.E. Kurczewski 15
50–100 females nesting simultaneously (Table 1). Tachysphex terminatus
and T. similis occurred in mixed aggregations at 17 locations, but some of
the sites were not given code numbers because of the low number of wasps
found and minimal information collected.
Soils. Females nested in brown, tan, white or gray fine gravel, coarse
sand, medium sand, fine sand, and loamy fine sand based on an analysis of
soils from all nesting sites (six of which are described in Table 2). Color
designation, hue, value, and chroma were not as important as soil particle
size in nesting-site soil characterization (Table 2).
Activity conditions. Females in central New York nested from May 29
(1962) to October 6 (1966) (Kurczewski and Acciavatti 1990). The latest
Figure 2. Man-made opening in sandy field, Inlet Valley, Ithaca, Tompkins County,
NY (TX-36). Tachysphex terminatus nested in level sand at bottom of slope.
Table 2. Soil characteristics at some Tachysphex terminatus nesting sites.
Site Soil particle size (%) Value/
No.1 Fg2 Cs3 Ms4 Fs5 Color Hue chroma
TX-1 34.1 46.9 13.7 5.3 Gray 5 Y 5/1
TX-2 1.1 16.0 56.1 26.8 Grayish brown 10 YR 4/2
TX-20 0.2 2.5 33.9 63.4 Pale brown 10 YR 6/3
TX-36 2.5 38.1 36.5 22.9 Grayish brown 2.5 Y 5/2
TX-54 55.1 40.7 3.1 1.1 Reddish yellow 7.5 YR 6/6
TX-56 9.7 60.0 23.6 6.7 Brown - -
1Table 1 provides a key and brief description for TX- sites.
2Fine gravel.
3Coarse sand.
4Medium sand.
5Fine sand + silt/clay.
16 Northeastern Naturalist Vol. 16, Monograph 3
emergence date at a central New York site (TX-20) was June 17 (1968).
There were two adult emergences annually in this region in late spring and
mid-summer. In eastern Kansas, females dug burrows from May 5 (1966) to
October 27 (1965). Nest provisioning was observed in eastern Kansas from
May 6 (1966) to October 18 (1965) and included several successive generations
of wasps.
Wasps were most active on bright sunny days when the air temperature in
the shade was 27–32 ºC. Females stopped nesting and rested on the sand at the
onset of moderate to dense cloud cover. Females exited overnight burrows in
Kansas as early as 0855 (CDT) at cell depth and sand surface temperatures
as low as 25 ºC and 28 ºC, respectively. Wasps hunted for prey on vegetation
and provisioned nests at sand surface temperature as low as 29 ºC. Females in
Kansas sometimes nested as late as 1830 (CDT). In New York, females exited
overnight burrows at cell depth and sand surface temperatures as low as 21.5
ºC and 24.5 ºC, respectively. Subsequent provisioning and temporary closures
occurred at sand surface temperature as low as 28 ºC.
Last generation females in Kansas (TX-54) were observed nesting or attempting
to nest through much of October 1965. Wasps excavated burrows,
leveled the removed sand, and made temporary closures at sand surface temperatures
of 33–37 ºC. One female was observed October 27, walking on the
sand and making low flights at a sand surface temperature of only 26 ºC.
In Kansas, more females provisioned nests at a sand surface temperature
of 47 ºC than any other temperature. Two females in Kansas provisioned
nests at sand surface temperatures as high as 64–65 ºC, while three wasps in
upstate New York brought prey to nests at sand surface temperatures as high
as 62–63 ºC.
In New York (TX-36, 20 June 1966), 10 females entered their nests and
stayed inside while eight wasps continued to bring in prey at sand surface
temperatures of 58–63 ºC. The females that entered burrows resurfaced
when the sand surface temperature decreased to 57 ºC.
Emergence. First generation females at one Kansas site (TX-56) began
emerging May 5, 1966. Emerging wasps were collected, frozen, and weighed
throughout the remainder of May. Recently emerged, first generation females
weighed, on average, 14.8 ± 3.2 mg (range = 11–21, n = 28). There
was weak correlation between date of emergence and size (weight) of first
generation wasps (r = 0.1317).
A last generation of wasps at another site in Kansas (TX-54) emerged in
early fall of 1965. Individuals collected 22 September–1 October had full
wings, unworn foretarsal digging rakes, and clean integument. Recently
emerged females rested on the sand surface and cleaned the sand grains from
their wings, antennae, and abdomen with their fore- and hindlegs. Within
minutes, males had located, hovered above in flight, mounted, and copulated
with them. Some females were mounted and copulated with twice during a
few minutes-long period.
Burrow excavation. A female searching for a place to dig a burrow walked
rapidly forward moving from side to side in a zigzag manner, held her wings
2009 F.E. Kurczewski 17
flat on her dorsum, and tapped her antennae on the soil surface. She pivoted
frequently, sometimes stopped, cleaned herself, resumed walking, or made a
low rapid flight to a new area. Females paused in certain spots, circled excitedly,
rapidly tapped their antennae alternately on the ground, and sampled
the soil with their mandibles. Their antennae were forked ventro-laterally,
their mid- and hindlegs were braced ventro-laterally against the substrate,
and their wings were held flat on the dorsum. Some wasps backed repeatedly
from the excavation, walked around the hole, and continued to dig with their
mandibles. During high sand temperatures (>54 ºC), females made brief
hovering flights, 5–8 cm high, turned one or two circles in mid-air, landed
facing the opening, and continued to dig.
As the mandibles loosened the soil, the forelegs were used in unison to
rake it backward beneath the synchronously lifting abdomen. The front tarsi
bear a series of long spines laterally and are well adapted for this purpose.
Females threw sand backward at the rate of 6–7 scuffs per second in direct
sunlight at 54 ºC sand surface temperature, as estimated from motion pictures.
The mid- and hindlegs were used only for walking. The wings were
held flat on the dorsum. The antennae were bowed downward, the tips alternately
tapping the sand surface.
In certain spots, a female dug down a few millimeters or centimeters,
using her mandibles and forelegs, but soon abandoned the excavation and
started to dig elsewhere. Three time consuming false starts were 31, 37, and
43 mm long. Such excavations were abandoned because the surrounding soil
caved in, the wasp encountered pieces of wood, stones, clay strata, hardpacked
soil or the nests of other insects, particularly ants, or perhaps she did
not receive appropriate stimuli to continue digging. Upon abandoning, some
females flew off directly or they turned away from the excavation and left
in flight or by walking (n = 16). Some wasps turned away from the opening
and threw sand backward into it with their forelegs before leaving (n = 16).
Females exhibiting the latter behavior spent 20–36 sec flinging sand into
the opening. Some wasps practiced both types of behavior upon abandoning
successive excavations. False starts were made 2–60 cm apart.
Forty-one females made 1–9 false starts before they remained in one
place and finished a burrow. They dug for 21 sec to 16.5 min (n = 34) and
removed 2–32 loads of sand from an excavation (n = 30) before leaving.
Abandoned excavations were 4–43 mm long (n = 11). Duration and length
of excavation were not correlated with whether or not a female flung sand
into the opening upon leaving. Not all wasps dug trial excavations before
completing a burrow. Some females remained in one place and finished the
burrow they started.
At intervals, a wasp backed from her excavation and removed the loose
sand that accumulated in the burrow and entrance (Fig. 3). The intervals,
as measured by the duration a female was inside her burrow and out of
sight, usually increased as she dug deeper (Fig. 4). The distances to which
females removed loose sand from their burrows increased as the excavation
advanced (Fig. 5). As sand accumulated in front of an entrance, the wasp
distributed it increasingly farther from the opening.
18 Northeastern Naturalist Vol. 16, Monograph 3
During later stages of an excavation, females extensively leveled the
accumulation in front of the entrance by walking in various directions
and flinging sand backward with their forelegs. Wasps moved laterally,
Figure 3. Female Tachysphex terminatus excavating burrow using her mandibles and
her forelegs in unison (TX-54). Her abdomen lifts synchronously as her forelegs fling
sand backward. Her antenna tips are held downward touching soil.
Figure 4. Mean interval (in seconds) between successive trips backward to remove
sand during burrow excavation plotted against sand removal number in Tachysphex
terminatus (bar graph averages in sets of five with standard error bars; TX-1, 20, 54).
2009 F.E. Kurczewski 19
diagonally, backward, and forward with respect to the direction of the
burrow. Standing sideways, females walked forward to the periphery of
the accumulation throwing sand back toward the center. Upon reaching
the edge of the accumulation, they turned around and moved toward the
center flinging sand in the direction of the periphery. Females also backed
to the periphery throwing sand and then moved forward to the center of
the accumulation flinging sand without turning around. During very late
stages of leveling, females stood several centimeters away with their
abdomen pointed toward the entrance and threw sand toward it. Regardless
of the directions of the leveling paths, the complexity of the patterns
increased as a female neared completion of her burrow (Fig. 6). After
sometimes spending several minutes leveling the sand accumulation in
Figure 5. Mean distance (mm) traveled to remove sand during burrow excavation
plotted against sand removal number in Tachysphex terminatus (bar graph averages
in sets of five with standard error bars; TX-1, 20, 54).
Figure 6. Leveling path for single sand removal
episode near end of burrow excavation
in Tachysphex terminatus (TX-1).
20 Northeastern Naturalist Vol. 16, Monograph 3
front of an entrance, a wasp moved forward into her burrow, often in a
straight line, flinging sand backward with her forelegs.
Extensive leveling where a female stood sideways and flung sand behind
her with her forelegs while moving in various directions was not noticeable
until about midway or later through an excavation. Fifty-two of 58
(89.7%) burrow excavations included extensive leveling in the latter half of
the process. One wasp (TX-1), digging in very damp coarse sand following
a rain, did not level the accumulation removed from burrow excavation.
The first extensive leveling was observed following 30–72 sand removal
episodes, 9–37 min after the start of an excavation (n = 58). The duration
spent leveling the accumulated sand in front of an entrance increased as the
complexity of the patterns intensified (Fig. 7). Near the end of an excavation,
some females spent 1 to 4.5 min for an individual leveling session on the
sand surface following a period of sand removal.
Females often interrupted distributing the loose sand, made a 5–30-cmhigh
hovering flight above the area, turning around once or twice in mid-air,
and landed facing the entrance. They then walked forward into the burrow
throwing sand backward. Such flights perhaps served as orientation to facilitate
future returns to the nest with prey. One excavating female made
50 trips backward with loose sand from the burrow, twice made a hovering
flight without turning, but turned completely around in mid-air while hovering
39 other times. Some wasps stopped leveling the accumulation, flew
to nearby vegetation, rested for several seconds, flew back to the area, and
recommenced distributing the loose sand.
Figure 7. Mean duration (in seconds) spent on surface distributing sand removed
from burrow excavation plotted against sand removal number in Tachysphex terminatus
(bar graph averages in sets of five with standard error bars; TX-1, 20, 54).
2009 F.E. Kurczewski 21
Females turned away from the entrance and threw sand toward it following
the last or last few sand removal episodes. The wasp later used this
loose sand for fill in making her temporary closure. Females periodically
stopped flinging sand backward and walked to the entrance up to 14 times
per excavation to examine the fill. If an entrance still remained open,
wasps turned away and threw sand toward it. After partly or completely
filling the opening, females reopened the entrance with the forelegs and
entered the burrow. A wasp then disappeared for 1.8–8.9 min (mean = 3.6
± 1.8, n = 52), pushed moist sand into the entrance from below, sometimes
closing it, while apparently shaping a cell at the end of the burrow.
Females digging in damp sand backed from an entrance up to 14 times
to clean their antennae by pulling them through the tibio-tarsal cleaning apparatus
of their front legs. Such cleaning probably ensured that the sensory
receptors on their antennae would function optimally. Females demonstrated
more antennal cleaning and much less leveling behavior when digging in
damp sand.
Wasps removed from their burrows stones or pieces of agglutinated soil
up to 3 mm in diameter with their mandibles. They deposited this debris
on the surface at distances of 15–45 mm from the entrance. Stones were
removed from an excavation 1–37 min after the start of digging. Up to 13
stones were removed from a burrow during an excavation.
After making the cell, females appeared headfirst in their entrances with
their wings held flat on their dorsum. They walked from the opening throwing
sand backward into it using their forelegs in unison. Some wasps even
used the tip of the abdomen to pack the loose sand in place. This comprised
the temporary closure of the entrance. Two females (TX-1) dug on a steep
slope, and the loose sand they threw backward rolled down the incline and
out of reach. Both wasps, when making their temporary closure, obtained
other sand that they loosened with their mandibles from the hard-packed
incline and flung with their forelegs into the opening. Females on level sand
proceeded as far as 30 mm from an entrance and spent 3–26 sec for closure
at various sand surface temperatures.
Some wasps interrupted their closure, turned around every few seconds,
and examined the fill, before turning back to throw more sand into the entrance.
After finishing the closure, some females turned toward it and then
took flight. Other wasps made circular orientation flights above the area
without turning around. During such a flight, females made 1–12 circles of
increasingly larger radii, at first flying 2–3 cm above the sand in circles
20–30 cm in diameter and later flying in circles 4–5 m wide. The wasps
frequently interrupted the flights to land on the sand surface or they flew to
nearby vegetation and rested momentarily.
The total number of sand removal episodes for excavation of a main burrow
and first cell was 28–76 (mean = 50.5 ± 12.5, n = 52; TX-1, 54). The
duration spent excavating a main burrow and first cell was 15–51 min (mean
= 32.1 ± 11.1, n = 60; TX-1, 54).
22 Northeastern Naturalist Vol. 16, Monograph 3
Additional cells. Females often excavated a side burrow and second cell
off the main burrow after stocking the first cell with grasshoppers and ovipositing
on a prey. Later, they sometimes dug additional side burrows and
up to five cells in the same nest. They packed most of the soil from the new
dig into the previous open burrow, working mainly beneath the surface and
out of sight. There were far fewer sand removal episodes per excavation for
an additional burrow and cell than for the main burrow and first cell. Wasps
appeared in their entrances 0–27 times (mean = 11.4 ± 9.0, n = 44) to remove
accumulated soil from the side burrow and cell. An orientation flight was
seldom made and, if so, it was brief in duration and never elaborate. Apparently,
the wasp retained enough information from the orientation flight(s)
following the excavation of the main burrow and first cell to enable her to
readily locate her entrance upon return with prey.
The initial indication that a female was digging a side burrow and second
cell was her backing into the entrance removing sand or, rarely, her
emergence headfirst to rake sand into the main burrow. The latter behavior
served to supplement the amount of soil needed to fill her first excavation
and occurred 2–17 min (mean = 9.9 ± 4.7, n = 46) after taking in the last
prey for the first cell. Females excavating a third burrow and cell backed
from an excavation removing sand for the first time an average of 13 min
from start.
Wasps backed out with sand for the new excavation at intervals of
0.5–6.5 min. Midway through this excavation, a female usually spent a
lengthy interval (2–7.5 min) inside transferring sand from the new burrow
to the main burrow leading to the first cell. The last interval inside the
nest was probably spent making a cell at the end of the side burrow, as
females were below ground and out of sight for 1.8–5.7 min (mean = 3.0
± 1.0, n = 33).
Females walked backward 0–32 mm (mean = 16.3 ± 8.0, n = 43) when
removing sand from the new side burrow and cell. Only three of 51 (5.9%) excavations
of additional cells included a semblance of leveling the slight sand
accumulation on the surface, and this leveling was seen only 2–5 times per
excavation. Five of 45 (11.1%) females turned to check the amount of fill in the
entrance 2–5 times per excavation. Antenna cleaning was rarely observed for
excavation of this later burrow and cell. Following the excavation, a wasp made
a 4–27-sec-long (mean = 9.6 ± 4.6, n = 36) temporary closure of the entrance,
throwing sand backward into it with her forelegs at varying sand surface temperatures.
Only four of 45 (8.7%) females turned to examine the amount of fill
in the entrance, and they made brief flights—perhaps for orientation—above
the area before leaving. The amount of time spent making the second burrow
and new cell was 10–49 min (mean = 20.6 ± 8.3, n = 42). One wasp (TX-54)
took 87 min to excavate a third burrow and cell at a sand surface temperature of
65 ºC, staying inside for long periods of time to avoid the hot sand.
Females in Kansas (TX-54) and New York (TX-36) completed up to four
fully provisioned cells per day in June, but only one per day in September–
October (TX-20, 54).
2009 F.E. Kurczewski 23
Rain burrows. At the approach of rain, some females quickly excavated a
short simple burrow in the sand with their mandibles and forelegs in unison
rather than remaining in a nest with prey. They closed themselves inside this
burrow in a head outward position after pushing damp loose sand upward
into the opening. This temporary burrow did not end in an enlarged ovoid
cell. The burrows were abandoned following the end of a rain and the reappearance
of optimal weather. Two such burrows entered the sand at about a
45° angle to the surface and were 37 and 41 mm long. They took 5–6 min to
excavate and included 17 and 18 sand removal trips, respectively.
Hunting. Females flew to a nearby source of vegetation to hunt for prey
after making an orientation flight. Some wasps hunted as far as 20 m from
the bare sand in which they nested. The females were able to hunt at such
distances from their nests because the relatively small grasshoppers they
captured were transported relatively quickly in flight. Wasps often made
consecutive provisioning flights to and from the same hunting areas.
Females searched for prey by hovering next to upright plants, flying
slowly 1–2 cm above and beside the leaves. After hovering around several
plants in succession without locating prey, a wasp landed, rested, and often
cleaned herself. Some females landed on plants and walked on the stems
and leaves tapping their antennae constantly. Frequently, they paused at the
petiole of plants with compound leaves and tapped their antennae rapidly.
If unsuccessful in capturing prey, females periodically returned in flight
to the nest, landed in front of the entrance, tapped their antenna tips on the
closure, turned away, and took flight, or they removed the sand fill, entered
the nest, exited several seconds later, re-closed the opening, and flew away.
One wasp returned without prey six times at 1–60 min intervals. Some females
without prey spent as long as 1–3 hours between consecutive returns
to the nest.
Grasshoppers were captured on plants, 7–11 m from the nests. From 1–3
stings were administered to the ventral thorax of a grasshopper near its leg
bases after the wasp pulled it from vegetation and, holding it, flew to the
ground. The paralyzed prey was then often transported directly to the nest in
flight without interruption.
Prey transport. A female straddled the grasshopper headfirst and usually
ventral side upward after stinging and, rarely, mandibulating the prey
and cleaning herself (Fig. 8). Infrequently, a wasp straddled her prey dorsal
side upward or on the side, but often quickly switched the grasshopper to the
ventral side upward position. Atypical prey transport in the dorsal side upward
position was probably related to the small sizes of the grasshoppers. Several
wasps brought tiny prey to the proximity of the nest headfirst and on the side.
A female grasped her prey by the bases of its antennae if ventral or dorsal side
upward or by the base of one antenna if on the side (Fig. 8). The grasshopper
was held by the antenna bases rather than farther out because of its small size.
Embracing the prey with all her legs and holding it tightly underneath, a wasp
took flight toward her nest. One wasp brought a very small grasshopper to her
nest in short low flights abdomen, not head, first!
24 Northeastern Naturalist Vol. 16, Monograph 3
Provisioning flights were often made straight to the nest, but some flights
included infrequent pauses and rests. Several females landed on soil or vegetation,
retained their mandibular grasp of the grasshopper’s antennae or one
antenna, but let loose its body and stood on all legs. The wasp’s abdomen
moved rapidly upward and downward as the individual segments moved
continuously back and forth breathing.
The mean ratio of weight of prey to wasp for flight transport was
0.7:1 (range = 0.20–2.31, n = 314) in first-generation New York females and
0.9:1 (range = 0.25–2.36, n = 277) in second-generation New York females.
Nineteen females with slightly larger than normal-sized prey, 10–11 mm
long, alternated flying with running on the ground, but always arrived at the
nest in flight. Nine wasps with grasshoppers, 12 mm long or longer, carried
the prey forward on the ground to the nest. These prey were probably too
heavy to be transported in flight, some weighing as much as 2.54–2.60 times
the wasp’s weight. Three females weighing 17, 18, and 21 mg transported
larger grasshoppers weighing 46, 50, and 58 mg (ratios: 2.7, 2.8, and 2.8:1),
respectively, from the prey capture sites to their nests entirely on the ground.
First-generation (May–June) wasps at one Kansas locality (TX-54,
1965) spent significantly less time obtaining consecutive prey items than
second- and later-generation (July–October) wasps from the same site:
mean = 10.4 ± 9.0 min, range = 1–48, n = 103 vs. mean = 46.2 ± 29.5
min, range = 3–189, n = 130 (P = 0.0134). First-generation (June) New
York wasps at one site (TX-1, 1964) averaged less time (mean = 11.4
± 8.3 min, range = 1–33, n = 39) between successive prey items than
Figure 8. Female Tachysphex terminatus resting on sand following lengthy flight
transport (TX-54). Wasp grasps the bases of grasshopper’s antennae with her mandibles
and, in flight, holds the prey’s body with her legs.
2009 F.E. Kurczewski 25
second-generation (mid-to-late July) wasps from that locality (mean = 39.3
± 21.7 min, range = 10–61, n = 13) (P = 0.0994).
Nest entry. A female with prey usually landed in front of the entrance.
She placed the grasshopper ventral side, rarely dorsal side, upward or on its
side with its head near the fill. Such a placement facilitated the wasp’s pulling
the prey into the nest by an antenna. The heads of 337 of 343 (98.3%)
grasshoppers at one site (TX-1) were positioned 0–40 mm (mean = 6.2 ±
5.4) from the bottoms of the entrances. The prey was nearly always placed
in a straight line or at a slight angle to the direction of the burrow. Only 25
of 878 (2.8%) grasshoppers were released to the left or right of the entrance
at roughly right angles to the direction of the burrow. Three females each
brought in two consecutive grasshoppers and placed both to the left of the
entrance at a right angle to the direction of the burrow.
One prey was transported to the nest headfirst and dorsal side upward,
released on the sand surface near the entrance, re-stung in its ventral thorax
twice, and dragged into the burrow in the usual manner. Seven grasshoppers
became wedged temporarily in entrances during prey entry into the burrow.
In all cases, the wasps were able to excavate around the grasshopper and
eventually take the prey into the nest.
After releasing the prey, a wasp walked to the closure and tapped her
antenna tips on the fill (Fig. 9). She then used her forelegs in unison to rake
open the filled entrance, throwing the loose sand backward beneath her abdomen
(Fig. 10). At high (55–65 ºC) sand surface temperatures females paused,
made 6–10 cm high hovering flights above the partly opened entrance turning
completely around in mid-air, landed facing the fill, and continued removing
Figure 9. Female Tachysphex terminatus, having released a paralyzed grasshopper on
the sand surface, searches for temporary closure with her antennae (TX-54).
26 Northeastern Naturalist Vol. 16, Monograph 3
the loose sand with their forelegs. The hovering flights were repeated a few
to several times, interspersed with bouts of raking sand backward, before
a wasp removed enough sand to enter her burrow. The female entered the
burrow headfirst, turned around inside (Fig. 11), walked up the burrow, and
Figure 10. Female Tachysphex terminatus begins to remove temporary closure using
her forelegs in unison (TX-54).
Figure 11. Female Tachysphex terminatus is inside her burrow. A paralyzed grasshopper
lies on the sand surface (TX-54).
2009 F.E. Kurczewski 27
appeared headfirst in her entrance 2–9 sec (mean = 4.0 ± 1.9, n = 1074) after
entering. She walked to the grasshopper, usually grasped it by the end of an
antenna with the mandibles (Fig. 12), and backed into the burrow dragging
the prey behind. The removal of temporary closure, entry without and with
Figure 12. Female Tachysphex terminatus grasps grasshopper by antenna with her
mandibles and begins dragging it backward toward open entrance (TX-54).
Figure 13. Female Tachysphex terminatus makes temporary closure, using her forelegs
in unison, after placing grasshopper in nest (TX-54).
28 Northeastern Naturalist Vol. 16, Monograph 3
prey, exit, and new temporary closure (Fig. 13) averaged about 30 sec, with
4–36 sec (mean = 9.5 ± 4.7, n = 974) spent to place the prey in the cell.
Six females exited their entrances, straddled the grasshopper headfirst
grasping it by one or both antennae and, with it, walked forward instead of
backing into the open burrow. The small size of the prey allowed the wasp
to enter the burrow atop the grasshopper. Three females, after turning around
inside and exiting, grasped the prey by a hindleg and pulled it backward into
the burrow. One wasp grasped the grasshopper by the end of its abdomen and
backed into the burrow. All of these grasshoppers were positioned in the cell
head outward, i.e., in the manner in which they were taken inside.
Wasps sometimes provisioned continually from mid-morning to late
afternoon regardless of sand surface temperature. Seven Kansas females
(TX-54) consecutively brought 8–16 grasshoppers to nests in 2–3 hours at
sand surface temperatures ranging from 40 to 65 ºC. Six New York females
(TX-36) consecutively arrived at nests with 8–23 prey over a 2–5 hour period
at sand surface temperatures ranging from 43 to 63 ºC. The cumulative
hours per female did not include the duration spent excavating additional
burrows and cells in nests.
Removal of the sand fill prior to nest entry and subsequent temporary
closure were made increasingly faster in a straight-line relationship as sand
surface temperature rose from 35 to 60 ºC (Figs. 14, 15). There was no difference
in removal of the sand fill or temporary closure activity rates and
duration of behavior at the same sand surface temperatures between New
York and Kansas females (Figs. 14, 15). Wasps made brief hovering flights
Figure 14. Mean duration of temporary closure removal (in seconds) plotted against
sand surface temperature (in degrees C) in Tachysphex terminatus (TX-1, 20, 36,
54, 56).
2009 F.E. Kurczewski 29
into cooler strata of air to avoid the hot sand from 55 ºC to 63 ºC (New
York)–65 ºC (Kansas), the mean number of such flights increasing gradually
up to 59–61 ºC (Fig. 16). Concurrently, wasps in Kansas and New York left
their entrances increasingly more open as they spent less time making the
Figure 16. Number of hovering flights per nest entry plotted against sand surface
temperature (in degrees C) in Tachysphex terminatus (TX-20, 36).
Figure 15. Mean duration of temporary closure (in seconds) plotted against sand surface
temperature (in degrees C) in Tachysphex terminatus (TX-1, 20, 36, 54, 56).
30 Northeastern Naturalist Vol. 16, Monograph 3
closures at higher sand surface temperatures. Leaving the entrance partly
open culminated at 59–65 ºC with gaps, 2–4 mm wide, at the tops of entrances
4.0–7.5 mm wide (Fig. 17). In cases where an entrance had been left
half or more open during a previous closure, the wasp simply ran inside in
<1 sec, with her forelegs feigning removal of the fill.
On very windy days, several prey were blown away from where they
were released near the entrance by the wasp. Other grasshoppers were accidentally
moved to an atypical position by the wasps. In each case, the
female flew or walked to the prey, straddled it, then walked or flew back to
the entrance, and repositioned the grasshopper with its head near the opening.
She then usually took it inside in the usual manner. However, some
wasps entered directly with the prey instead of going into the burrow and
turning around inside.
Many females, upon removing the fill from an entrance, threw sand atop
the grasshopper. Having gone into their burrows, such wasps came completely
outside, stood over the prey, and, using their mandibles and forelegs, removed
most of the sand grains before reentering the nest, coming out, and backing in
with the grasshopper. After placing the prey inside, the female reappeared in
her entrance headfirst and temporarily closed the entrance with sand.
Females nesting in close proximity sometimes laid their prey near the
entrance, went inside, came out, and found another female trying to steal
the grasshopper. The intruder often flew away at the sight of the resident
female emerging from her entrance. The resident then picked up her prey
with her legs and mandibles and flew in circles over the area for a few
Figure 17. Number of observations of various nest entry behaviors plotted against
sand surface temperature (in degrees C) in Tachysphex terminatus (TX-20, 36).
2009 F.E. Kurczewski 31
seconds. She landed, placed her grasshopper in front of the entrance, and
went through the sequence of placing it in the nest as described above.
Several instances of prey stealing were observed where females nested
in close proximity, especially when two wasps shared a common entrance.
Grappling between a resident and intruder using their mandibles and legs
was commonplace, during which the grasshopper was passed back and forth
among the two wasps. This behavior sometimes culminated with the usurper
quickly taking the stolen prey into her nest. Following the loss, the resident
female searched for many minutes by running excitedly on the sand and
making rapid short circular flights above the area of the skirmish.
Final closure. A few females, before closing, appeared headfirst in
the entrance several minutes after taking in the last prey, turned around
outside, and reentered and re-exited the burrow from one to four times in
succession. A wasp began her final closure inside the nest, sometimes producing
a buzzing sound as she pulled down soil from the top and sides of
the burrow with her mandibles. Keeping her abdomen pointed toward the
cell, she flung the loose soil backward with her forelegs in unison beneath
her synchronously lifting abdomen. The soil was tamped into place with
the rapidly vibrating end of her abdomen. An audible buzzing sound often
accompanied this activity. Her mid- and hindlegs were braced against the
lower sides of the burrow. Her wings were held flat on her dorsum. Her antennae
were spread ventro-laterally and sometimes held against the burrow
walls, perhaps aiding in centering the blows from the end of her abdomen.
Once the female filled the burrow, preventing her from backing inside, her
antennae were no longer held against the burrow walls while tamping the
fill with her abdomen.
A wasp appeared in her entrance for the first time to obtain sand from
the surface 0.5–20.0 min (mean = 6.3 ± 4.6, n = 33) after taking in the last
prey. As she walked onto the surface, her forelegs, working in unison,
continuously raked sand backward beneath her synchronously vibrating
abdomen. Her apical foretarsal segments were bent medially to expose
more tarsal spines for catching and moving the sand grains. Most females
walked forward onto the sand surface in a straight or nearly straight direction.
As the wasp raked sand backward into the burrow, her antennae were
held downward, away from the head, the tips tapping the floor. She held
her wings flat on her dorsum.
At first, females stayed outside only a second or two getting sand and
then backed rapidly into the burrow throwing the loose sand backward with
their forelegs. Later, they remained on the surface for longer periods of
time flinging sand backward (Fig. 18). Females walked from their entrances
increasingly farther to get sand as the closure went to completion and loose
soil near the entrance was depleted (Fig. 19). The intervals at which a wasp
came outside, as measured by the duration she was in the burrow, decreased
between consecutive trips for soil (Fig. 20). As the wasp filled her nest, she
did not have to back down or move up the burrow as far to obtain sand.
32 Northeastern Naturalist Vol. 16, Monograph 3
Wasps exited their burrows to get sand for the closure 6–48 (mean = 17.4
± 8.7, n = 31) times. Cleaning the antennae and mandibles once or twice in
Figure 18. Mean duration (in seconds) spent on surface raking sand backward into
burrow for final closure plotted against sand retrieval number in Tachysphex terminatus
(bar graph averages in sets of five with standard error bars; TX-1, 20, 54).
Figure 19. Mean distance (mm) to which wasps walked to get loose sand for final
closure plotted against sand retrieval number in Tachysphex terminatus (bar graph
averages in sets of five with standard error bars; TX-1, 20, 54).
2009 F.E. Kurczewski 33
the entrance or on the surface was seen during 5 of 31 (16.1%) closures.
Females turned toward the entrance to examine the fill 1–19 (mean = 5.7 ±
4.5, n = 27) times during a closure. Seven of 31 (22.6%) wasps, while filling
burrows, made 1–10 hovering and turning flights above the area during
periods of high sand surface temperature (>54 ºC). They turned around completely
once or twice in mid-air, landed facing the entrance, turned away, and
raked sand backward. Near the end of the closure, females walked in various
directions on the surface and, keeping their abdomens pointed toward the
entrance, threw sand backward onto the fill for 0.5–3.5 min (mean = 1.5 ±
0.8, n = 30).
Atypical final closures were seen infrequently. A few females walked
onto the surface to get sand, turned around, and, instead of backing into
the burrow, entered headfirst flinging sand backward up to seven times per
excavation before closing in the usual manner. Females that nested in steep
sandbanks were unable to obtain loose soil from near the entrance because it
had fallen out of reach. This situation required the wasp to use her mandibles
nearly continuously to break down the top and sides of the burrow to get soil
for the closure. She pulled the fallen loose soil backward with her forelegs
and tamped it in place with the vibrating end of her abdomen. The duration
of final closure varied with different wasps and their nesting situations, ranging
from 6 to 34 min (mean = 13.9 ± 7.9, n = 27).
Nest structure and dimensions. Females excavated short, shallow one- to
five-celled nests that entered the soil obliquely at an angle with the surface
Figure 20. Mean interval (in seconds) between successive exits to obtain sand for
final closure plotted against sand retrieval number in Tachysphex terminatus (bar
graph averages in sets of five with standard error bars; TX-1, 20, 54).
34 Northeastern Naturalist Vol. 16, Monograph 3
ranging from 14–41°, except for nests dug into steep slopes. Three-celled
nests were the rule under optimal nesting conditions, but some wasps made
four- and five-celled nests when conditions were appropriate (Fig. 21). Some
nests with only one fully provisioned cell were closed prematurely at the
onset of rainfall, extremely cloudy weather, and dusk. Eight pairs of females
at one site (TX-1) shared common entrances due to limited space and high
density of wasps.
Figure 21. Representative configurations of Tachysphex terminatus (top), T. similis
(middle), and T. a. apicalis (bottom) bi- and multi-cellular nests. Numbers indicate
order in which cells were made. Scale refers to all nests.
2009 F.E. Kurczewski 35
With abundant prey, nesting space, and optimal weather, a second and,
often, third or fourth burrow were excavated off the main one, each terminating
in a cell. Side burrows leading to second cells left the main burrows
at distances of 8–90 mm (mean = 32.7 ± 20.2, n = 63) from the entrances.
Side burrows leading to third cells left the main burrows at distances of
13–64 mm (mean = 41.9 ± 19.0, n = 10) from the entrances. Distances between
first and second cells were 22–74 mm (mean = 41.6 ± 13.5, n = 53),
between second and third cells were 22–66 mm (mean = 39.6 ± 15.2, n =
11), and between third and fourth cells was 24 mm (n = 1).
In attempting to excavate a side burrow and cell, a wasp sometimes encountered
clay, stones, roots, pieces of wood, and other debris resulting in an
incomplete burrow or spur. During inclement weather, a female sometimes
turned around and rested head outward inside the spur. Spurs were exceedingly
rare in bare sand where there was little or no subterranean debris. Spurs
were found in 28 of 279 (10.0%) nests at two sites (TX-1, 54). Spurs were
13–36 mm long (mean = 24.8 ± 8.4, n = 28).
Most burrows were straight or bent slightly as they penetrated the soil
(Fig. 21). Of 456 burrows examined for lateral curvature, 185 (40.6%) bent
to the left or right at angles greater than 22.5°. Two hundred seventy-one
(59.4%) burrows were straight or exhibited a lateral curvature of less than
22.5°. Different aggregations showed much variation in burrow curvature.
Only 12 of 82 (14.6%) burrows excavated in 1961–1962 at one site (TX-1)
were bent more than 22.5°. However, 69 of 95 (72.6%) burrows dug at two
other locations during 1962–1963 (TX-2, 20) exhibited lateral curvature of
more than 22.5°.
Burrows were 3.5–5.5 mm in diameter, enlarging at the entrances to 4.0–
7.5 mm. The smaller measurements were from hard-packed soil and/or smaller
females, and the larger measurements from loose coarse sand and/or larger
females. Main and side burrows usually terminated in cells that were oval or
elongate-oval in shape. Cell height, width, and length were rather uniform at
the various locations. One hundred eighty-four of 190 (96.8%) cells were 6–9
mm high and wide and 10–15 mm long. Variation in cell size was related to
differences in soil texture and moisture, perhaps influenced by generation of
wasp, size of female, number of prey, and aggregate prey weight.
The longest and deepest nests were located in undisturbed, loose coarse
sand in southern New Jersey, eastern Kansas, and Presque Isle State Park,
PA. The shortest and shallowest nests were found in compact, loamy fine
sand of man-made sandpits and sandbanks in central New York (Table 3).
Longer burrows and deeper cells characterized first generation (spring)
nests, and shorter burrows and shallower cells were typical of second- and
later-generation (mid-late summer) nests at nearly all sites in New York and
Kansas (Table 3). There was a certain cell order in some three-celled nests,
but no distinct cell order in sequential positioning or cell depth within a nest
in four- and five-celled nests (Fig. 21). There was no correlation between
wasp size (weight) and cell depth (r = -0.1800).
36 Northeastern Naturalist Vol. 16, Monograph 3
Prey. Females preyed exclusively on small nymphal Acrididae and,
very rarely, small nymphal Tettigoniidae (Kurczewski 1966a). Most wasps
were rather unselective of the genera and species of Acrididae as long as it
was of appropriate size. Sixteen genera and 22 species of acridid prey were
identified from 2367 specimens (Table 4). Another 1000 or so specimens
Table 3. Burrow length and cell depth in Tachysphex terminatus nests.3
Site Burrow length (mm) Cell depth (mm)
TX-year4 n Range Mean ± SD5 n Range Mean ± SD
12-1960 25 41–86 62.0 24 25–61 43.0
11-1961 13 42–110 80.0 13 25–65 50.0
12-1961 30 35–90 62.0 44 16–54 40.0
11-1962 87 45–105 72.0 146 22–75 42.0
12-1962 7 52–67 58.7 ± 5.65 8 28–35 32.0 ± 2.45
11-1963 10 50–65 56.8 ± 5.45 16 35–49 43.1 ± 3.61
11-1964 30 40–108 65.3 ± 12.56 34 29–59 44.8 ± 8.74
11-1967 1 54 54.0
21-1962 5 79–101 93.0 5 38–50 46.0
22-1962 12 32–67 45.0 12 16–29 21.0
21-1963 5 47–98 72.2 ± 21.08 8 16–55 40.3 ± 15.06
22-1963 12 33–72 56.6 ± 11.13 14 15–36 25.5 ± 6.30
102 2 62–76 69.0 ± 9.90 2 34–48 41.0 ± 9.90
191 2 65–69 67.0 ± 2.83 2 39–45 42.0 ± 4.24
192 11 43–105 61.4 ± 17.34 12 25–59 34.4 ± 11.08
201-1963 18 34–118 64.5 ± 23.78 19 18–41 26.1 ± 7.75
202-1963 62 38–80 52.5 ± 10.06 67 17–39 25.6 ± 4.60
20-1964 40 47–114 74.4 ± 18.93 40 19–63 38.1 ± 10.84
202-1967 5 15–20 17.6 ± 2.07
241 1 82 82.0 2 42–52 47.0 ± 7.07
261 3 93–106 99.3 ± 6.51 5 35–54 46.9 ± 6.98
271 2 66–68 67.0 ± 1.41 2 51–55 53.0 ± 2.83
311 4 74–79 76.3 ± 2.63 4 44–60 51.3 ± 7.18
351 1 102 102.0 1 58 58.0
362-1963 20 45–99 59.5 ± 17.09 21 18–39 27.7 ± 5.91
36-1964 6 57–104 78.2 ± 17.01 6 24–47 33.0 ± 9.40
382 3 105–129 119.3 ± 12.66 3 62–69 65.7 ± 3.52
412 7 49–69 59.7 ± 6.78 9 25–41 32.4 ± 5.53
442 14 44–72 55.6 ± 8.51 15 22–34 28.6 ± 3.94
481 4 56–85 70.5 ± 12.66 5 30–44 37.2 ± 5.72
502 13 51–73 65.1 ± 6.86 13 19–51 34.0 ± 8.40
542-1964 3 49–90 73.3 ± 21.55 3 19–34 28.7 ± 8.39
541-1965 33 65–165 121.3 ± 26.00 33 36–76 53.9 ± 11.89
542-1965 41 37–73 54.2 ± 9.73 41 18–37 24.1 ± 4.12
561 4 58–84 70.8 ± 11.87 4 29–56 38.3 ± 12.18
601 6 78–126 99.7 ± 19.83 6 31–65 43.0 ± 13.16
692 2 64–66 65.0 ± 1.41 2 49–54 51.5 ± 3.54
951 1 49 49.0 1 26 26.0
991 3 59–67 62.7 ± 4.04 3 27–33 30.0 ± 3.00
1Spring generation.
2Summer generation(s).
3Includes cell length and cell height, respectively.
4Table 1 provides a key and brief description for TX- sites.
5SD values given where available.
2009 F.E. Kurczewski 37
remain unidentified, so the number of prey genera and species might be
half again higher than that number. The subfamilies of Acrididae taken as
prey were Cyrtacanthacridinae + Melanoplinae, 1661 specimens (70.2%);
Gomphocerinae, 396 (16.7%); and Oedipodinae, 310 (13.1%). As many as
three subfamilies and four genera and species of grasshoppers were found
in a single cell.
There was a distinct difference in the acridid species from first and second
generation New York nests. Chloealtis conspersa, Chorthippus curtipennis,
Dissosteira carolina, Melanoplus bivittatus, M. keeleri, and M. sanguinipes
were prevalent in June–early July nests, but conspicuously absent later in the
summer. Encoptolophus sordidus and Melanoplus femurrubrum prevailed in
late July–August nests. In Kansas, Ageneotettix deorum, Boopedon gracile,
Melanoplus differentialis, M. sanguinipes, M. spp., and Syrbula admirabilis
were noteworthy prey in May–June cells. Arphia simplex and Chortophaga
viridifasciata were prevalent in late summer–fall Kansas cells.
A fall generation of T. terminatus in Kansas (TX-54, 1965) stocked a
preponderance of these two species in 38 cells. Prey collected from the cells
included 71 specimens of Arphia simplex, 30 Chortophaga viridifasciata, and
1 Melanoplus femurrubrum. A sample of nymphal grasshoppers of suitable
prey size net-swept from vegetation where the wasps were hunting yielded:
80 specimens of Chortophaga viridifasciata, green and gray-streaked color
forms, 33 Arphia simplex, and 1 Melanoplus femurrubrum. Only grasshoppers
equivalent in weight to those stocked in the cells (1–50 mg) were
counted, 104 being in the 20–50 mg range and 10 in the 1–19 mg range. The
Table 4. Species of prey of Tachysphex terminatus, listed in alphabetical order.
Species of prey (nymphs) No. specimens
Ageneotettix deorum Scudder 14
Arphia simplex Scudder 119
Arphia xanthoptera (Burmeister) 1
Boopedon gracile Rehn 64
Chloealtis conspersa (Harris) 27
Chorthippus curtipennis (Harris) 255
Chortophaga viridifasciata (DeGeer) 82
Dichromorpha viridis (Scudder) 11
Dissosteira carolina (Linnaeus) 16
Encoptolophus sordidus (Burmeister) 92
Melanoplus bivittatus (Say) 895
Melanoplus differentialis (Thomas) 39
Melanoplus femurrubrum (DeGeer) 427
Melanoplus keeleri (Thomas) 139
Melanoplus s. sanguinipes (Fabricius) 78
Melanoplus spp. 75
Mermiria sp. 1
Orphulella speciosa (Scudder) 5
Pardalophora apiculata (Harris) 1
Phlibostroma quadrimaculatum (Thomas) 4
Schistocerca americana (Drury) 7
Syrbula admirabilis (Uhler) 15
38 Northeastern Naturalist Vol. 16, Monograph 3
vegetation was net-swept for one hour each day from 22 September through
18 October at a time when the wasps hunted.
The number of grasshoppers stocked in fully provisioned cells at a single
locality ranged from 1–14 (TX-1; Table 5). Wasps usually stocked three or
more prey per fully provisioned cell. Cells that contained only one or two
grasshoppers were often closed prematurely in response to oncoming bad
weather or the onset of dusk. Cells of first-generation New York and Kansas
aggregations usually contained more prey, often twice as many, as cells of
second or later generations of wasps (Table 5). In multi-celled nests with
fully provisioned cells, cell 1 contained slightly more prey (mean = 4.4 ± 2.4,
Table 5. Number of prey and aggregate prey weight per cell in Tachysphex terminatus nests.
Site No. prey per cell Aggregate prey wt. (mg)
TX-year3 n Range Mean ± SD n Range Mean ± SD
12-1960 5 2–4 3.4 ± 1.73
11-1961 6 5–9 7.5 ± 1.38
12-1961 12 2–5 3.8 ± 1.22
11-1962 90 1–12 5.7 ± 2.37
12-1962 5 2–4 2.4 ± 0.89
11-1963 16 2–9 5.8 ± 2.17 16 38–128 81.8 ± 27.87
1-1964 27 3–14 6.1 ± 2.73 27 27–196 77.4 ± 37.85
11-1967 1 7 7.0 1 85 85.0
21-1962 4 4–8 6.5 ± 1.73
22-1962 7 1–6 3.3 ± 1.72
21-1963 7 4–11 6.6 ± 2.41 5 37–152 81.6 ± 38.93
22-1963 14 1–7 3.9 ± 2.22 12 24–120 70.4 ± 31.53
191 1 6 6.0 1 125 125.0
192 10 1–6 2.2 ± 1.48 10 25–68 42.9 ± 10.53
201-1963 18 1-7 4.6 ± 1.76 14 29-142 72.9 ± 30.25
202-1963 61 1-8 3.1 ± 1.36 61 26-131 61.0 ± 25.07
20-1964 32 1–6 3.4 ± 1.24 32 33–148 81.2 ± 29.65
241 1 2 2.0
261 4 4–7 5.3 ± 1.50
311 3 5–7 6.0 ± 1.00 3 25–113 80.7 ± 48.42
362-1963 21 1-5 2.8 ± 0.98 21 31-130 65.8 ± 32.38
36-1964 5 2-6 2.8 ± 1.51 5 51–110 76.8 ± 23.77
382 7 3–10 5.9 ± 2.12
412 3 2–5 3.7 ± 1.72
442 11 1–4 2.5 ± 0.93
481 4 4–7 6.3 ± 1.50
502 5 1–4 2.4 ± 1.14 5 32–70 46.0 ± 14.56
542-1964 2 3-6 4.5 ± 2.12 2 78–100 89.0 ± 15.56
541-1965 33 2-10 5.9 ± 2.16 27 50-140 97.1 ± 28.00
542-1965 43 1-4 2.8 ± 0.92 38 20-125 61.3 ± 26.23
562-1964 1 3 3.0 1 111 111.0
561-1965 3 6 6.0 ± 0.00 2 27-59 43.0 ± 22.62
601 5 4-7 5.4 ± 1.34 5 46-92 66.7 ± 20.49
692 2 2-3 2.5 ± 0.71 2 27-34 30.5 ± 4.95
991 3 6-7 6.7 ± 0.58
1Spring generation.
2Summer generation(s).
3Table 1 provides a key and brief description for TX- sites.
2009 F.E. Kurczewski 39
range = 1–14, n = 98) than cell 2 (mean = 3.9 ± 2.0, range = 1–9, n = 68), but
not cell 3 (mean = 4.8 ± 2.7, range = 1–10, n = 16). Four and five prey were
found in two fully provisioned fourth cells.
Most of the grasshoppers that females stocked in their cells were the
same size and weight or smaller and lighter in weight than the wasps. Prey
individuals ranged from 3.5 mm (Melanoplus bivittatus) to 13.5 mm (Chorthippus
curtipennis) in body length. In New York, grasshoppers collected
from first-generation cells weighed 3–52 mg (mean = 14.0 ± 9.7, n = 224),
while prey taken from second-generation cells weighed 5–58 mg (mean =
19.6 ± 9.9, n = 325) (P = 0.057). In Kansas, individual prey from spring cells
weighed significantly less (mean = 13.2 ± 9.0 mg, range = 4–52, n = 184)
than prey from summer–fall cells (mean = 21.0 ± 11.5 mg, range = 3–52,
n = 173) (P < 0.05). A few of the larger prey individuals (>40 mg) from both
New York and Kansas had one hindleg missing.
First-generation prey from New York and Kansas, including those collected
from wasps, weighed, on average, significantly less than prey from
second and later generations: New York (1963–1964)—first-generation
mean = 12.7 mg, range = 3–52, n = 346; second-generation mean = 20.6 mg,
range = 4–58, n = 504 (P < 0.05); Kansas (1964–1965)—first-generation
mean = 13.8 mg, range = 4–52, n = 233, second- and later-generation mean
= 19.4 mg, range = 3–52, n = 230 (P < 0.05).
In multi-celled nests, the mean aggregate prey weight for cells 1, 2, and 3
supported the mean number of prey per cell data: cell 1 mean = 76.4 ± 35.5 mg,
range = 13–196, n = 83; cell 2 mean = 73.8 ± 29.1 mg, range = 18–148, n = 57;
and cell 3 mean = 84.9 ± 36.4 mg, range = 20–128, n = 14. The aggregate prey
weight of one cell 4 was 108 mg. Cells with the lowest aggregate prey weights
were often closed prematurely at the onset of inclement weather.
There was a substantial reduction in the prey biomass per fully provisioned
cell from first to second and later generations in New York and
Kansas as indicated by a decrease in the aggregate prey weight per cell: New
York (1963–1964)—generation 1 mean = 84.0 mg, range = 28–196, n = 56;
generation 2 mean = 65.3 mg, range = 24–148, n = 156 (P = 0.091); Kansas
(1964–1965)—generation 1 mean = 94.4 mg, range = 27–140, n = 32; generation
2 mean = 58.9 mg, range = 20–125, n = 50 (P = 0.075) (Table 5).
This reduction resulted in first-generation wasps being slightly smaller and
lighter in weight than second or later generation wasps: New York—spring
mean = 19.3 ± 4.1 mg, range = 11–27, n = 9; summer mean = 20.7 ± 2.3 mg,
range 17–25, n = 7 (t = -0.5041, P = 0.6322, df = 8); Kansas—spring mean =
14.8 ± 3.6 mg, range = 10–21, n = 26, summer mean = 18.6 ± 2.9 mg, range
= 14–24, n = 12 (t = -3.4931, P = 0.0023, df = 20). New York females were
significantly heavier (mean = 19.9 ± 4.9 mg, range = 11–27, n = 16) than
Kansas females (mean = 15.7 ± 4.0 mg, range = 10–24, n = 49) (t = 1.7247,
P = 0.0254, df = 20).
Six hundred fifteen of 730 (84.2%) prey were positioned head inward and
ventral side upward or on their side in the cells. One hundred five (14.4%)
40 Northeastern Naturalist Vol. 16, Monograph 3
grasshoppers were placed head inward and dorsal side upward in the cells.
Six prey were put head outward and ventral side upward, and four grasshoppers
were placed head outward and dorsal side upward in the cells. Cells that
contained the largest number of prey usually had more grasshoppers placed
in atypical positions. The wasps, in maneuvering to oviposit after bringing in
their last prey, may have accidentally moved some of the grasshoppers from
their typical head inward and ventral side upward positions to the atypical
positions in which some of them were found.
Some prey were not placed in a cell. Four nests had several grasshoppers
aligned almost single-file in the burrow. Six of nine prey in one nest were positioned
that way, with one grasshopper lying halfway between the cell and
entrance. A single-celled nest with 14 grasshoppers had four of them aligned
in the burrow in front of the cell because they couldn’t all fit in the cell.
Egg. The wasp’s egg was usually laid on a grasshopper at the bottom
of the cell, near the back end, in cells with three or more prey. An egg was
almost never placed on prey at the front of the cell because this grasshopper
would be the first one attacked by enemies entering a nest. The prey to which
the egg adhered was positioned head inward and ventral side upward or on its
side in 478 of 497 (96.2%) cells. Twelve eggs were put on grasshoppers that
were placed head inward and dorsal side upward, 4 on prey put head outward
and dorsal side upward, and 3 on grasshoppers positioned head outward and
ventral side upward. Some prey placed head outward occupied cells that
were closed prematurely at the onset of inclement weather.
The grasshopper to which the egg was attached was often the largest
and heaviest prey in the cell. Two hundred eleven of 300 (70.3%) eggs were
affixed to the heaviest grasshopper in the cell, 53 (17.7%) to the second
heaviest, 16 to the third heaviest, 6 to the fourth heaviest, and 14 to the lightest
prey in the cell. Eleven cells held only a single prey. Eggs were placed
on grasshoppers that weighed 5–58 mg (mean = 25.8 ± 10.9, n = 290), while
other prey in the cells had a mean weight of 15.4 ± 9.6 mg (n = 869) (P <
0.05). Excluding cells with only a single grasshopper, egg-bearing prey comprised
the first (20 examples), second (32), third (16), fourth (2), fifth (4) or
sixth (4) individuals taken into entrances.
A wasp’s egg was attached to the soft intersegmental membrane surrounding
the base of a grasshopper’s forecoxa by the less tapered, distal end. The
proximal end extended free to the opposite side, the egg lying transversely
across the pro- and mesosterna between the bases of the fore- and midcoxae
(Fig. 22). Of 486 eggs attached to prey, 223 (45.9%) were affixed to the base
of a left forecoxal intersegmental membrane and 263 (54.1%) to the base of a
right forecoxal intersegmental membrane. Eighty-two of 114 (71.9%) eggs in
two-celled nests were both attached to the same (left or right) side of the base
of a prey’s forecoxal intersegmental membrane. Only twelve of 53 (22.6%)
eggs in three-celled nests were all placed on the same side of the base of a
grasshopper’s forecoxal intersegmental membrane.
2009 F.E. Kurczewski 41
Figure 22. Tachysphex terminatus egg (arrow) lying transversely across thorax of
Melanoplus sp. between bases of fore- and midcoxae (TX-1). Egg is affixed to soft
intersegmental membrane surrounding base of prey’s right forecoxa.
42 Northeastern Naturalist Vol. 16, Monograph 3
The wasp’s egg was slightly curved, sausage-shaped, white or creamcolored,
and measured (live) 1.6–2.1 mm (mean = 1.88 ± 0.11, n = 122) long
and 0.4–0.6 mm (mean = 0.45 ± 0.05, n = 122) wide.
Development. Five eggs from Kansas (TX-54) and 10 eggs from New
York (TX-1), all from first-generation females, were followed through larval
development to adult emergence. A total of five of the 15 (33.0%) eggs did
not complete development and emerge.
Eclosion from egg to larva occurred in about 42–48 hours at 27–32 ºC air
temperature. The small (2 mm long) larva remained affixed to its grasshopper,
feeding at the site of the egg attachment for an additional day. Larvae, 3.5–
4.0 mm long, were seen feeding in the cervical region of the grasshopper
the following day. The larvae rapidly grew to 4.5–5.0 mm, devoured much
of their pedestal prey, and moved to feed on other grasshoppers nearby. The
larvae were ca. 8–9 (male) to 9–11 (female) mm long when they began to
construct a cocoon of silk, saliva, and the surrounding sand grains. Initiation
of cocoon construction occurred 5–6 days after oviposition. The ovoid
cocoons, averaging 9.5 mm long and 5.0 mm wide, were completed on the 6th
or 7th day. Female cocoons were slightly larger than male cocoons. Female
emergence occurred 30–34 days after oviposition; males took 29–33 days to
complete development and emerge. One female emerged 56 days after being
laid as an egg.
Tachysphex similis
Literature review
Krombein and Evans (1955) reported a female of T. similis straddling
an immature Radinotatum (= Achurum) sp., probably carinatum (Walker)
(Gomphocerinae) on the sand at Marco, Collier County, fl. The wasp held
the grasshopper with her mandibles by the bases of its antennae.
Krombein (1964) observed a female of this species excavating a burrow
in sandy soil at the Archbold Biological Station, Highlands County, fl. She
removed sand from the burrow using her forelegs simultaneously, raised her
abdomen synchronously as the sand was flung backward, and kept her wings
flat on the dorsum. This wasp spent much time on the surface, leveling the
sand removed from the burrow.
Krombein (1964) noted a second female on the sand flats along the Peace
River, just west of Arcadia, De Soto County, fl. She flew in with prey, released
the grasshopper about a centimeter from the entrance, removed the
temporary sand closure, entered, came out, grasped the prey, and pulled it
into the burrow headfirst. The nest was incompletely provisioned. The entrance
was 4 mm wide. The straight burrow, 7.5 cm long, ended in a cell, 6 cm
beneath the surface. The cell held five Melanoplus nymphs, 5–6 mm long.
Krombein (1964) observed a third female nesting in flat, bare sand
near Lake Annie, Highlands County, fl. She entered her nest with prey
as described above and then made a final closure. During the closure, she
repeatedly backed down the burrow with sand obtained from the surface.
2009 F.E. Kurczewski 43
The burrow went downward at a shallow angle for 2.5 cm and then descended
almost vertically to a cell at a depth of 3 cm below the surface. The fully
provisioned cell contained three Aptenopedes sp. and one Melanoplus sp.,
5–8 mm long. The wasp’s egg, 2 mm long, was attached to the right forecoxa
of the largest prey in the cell and laid between the fore- and midcoxae. A second
cell was found ca. 4 cm from the first cell. It was located 4.5 cm beneath
the surface and held 10 nymphal Aptenopedes sp., 5–8 mm long. The wasp’s
egg was affixed to a medium-sized prey as described above.
Kurczewski (1967) outlined the nesting behavior of T. similis in a study
on its cleptoparasite, Hedychridium fletcheri Bodenstein (Chrysididae). The
female first excavated a slanting burrow and terminal cell in sandy soil. She
temporarily closed the entrance with loose sand and then flew to vegetation
where she searched for and stung a small nymphal grasshopper. The wasp
returned in flight to her nest with the prey, landed near the filled entrance, removed
the sand closure, entered, exited, pulled the grasshopper into the nest,
came out, closed the entrance with sand, and flew off in search of another
prey. She repeated this provisioning sequence until the full complement of
prey was placed in the cell. A fully provisioned cell may contain more than
a dozen small grasshoppers. After laying an egg on one of the prey, the wasp
permanently filled the burrow leading to the cell with sand and excavated a
new burrow elsewhere or she dug and provisioned up to four other cells in
the same nest.
Elliott and Kurczewski (1985) presented information on two nests of T.
similis from Wamego, Pottawatomie County, KS. One nest was single-celled
and contained three prey. The second nest had four cells with three, three,
five, and three prey identified as Melanoplus sp. (8 examples), Mermiria sp.
(1), Oplia obscurus (Thomas) (2), and Pseudopomala brachyptera (Scudder)
(8). Although not reported in their study, females collected from this
site weighed 9.8–13.2 mg (mean = 11.7, n = 5). Prey grasshoppers taken
from the nests or wasps averaged 10.3 mg (range = 1.8–20.8, n = 19). Eggbearing
prey weighed 8.7–17.1 mg (mean = 13.3, n = 4). Other prey in the
cells averaged 9.5 mg (range = 1.8–20.8, n = 15). Aggregate prey weight per
cell averaged 38.5 mg (range = 28.6–53.2, n = 4).
Pulawski (1988) recorded a female of T. similis from Marco, flpinned with a juvenile Schistocerca sp. and another wasp from St. Catherine
Island, Liberty County, GA pinned with a nymphal Melanoplus
devastator Scudder.
Elliott (1996) observed females of T. similis nesting at three locations
in The Bahamas: San Salvador Island, Cat Island, and Great Abaco. Wasps
nested throughout much of the year, being absent only from November to
February. Nesting sites occupied “hard-packed sand” and loose beach sand.
The aggregation on San Salvador Island contained 18 active nests with conspecific entrances as close together as 7 cm. Females began excavations
from flat sandy surfaces removing the pebbles with their mandibles. Burrow
excavation was as described above. Burrow excavation duration ranged from
44 Northeastern Naturalist Vol. 16, Monograph 3
23 to 49 min. Females made 27–32 trips into their burrows to remove sand
during an excavation. Time spent inside the burrow increased as a dig went
to completion. Wasps spent much time on the surface toward the end of an
excavation, leveling the sand removed from the burrow. Following burrow excavation,
females temporarily closed their entrances with sand and then made
circling orientation flights above the area before flying off to hunt prey. Wasps
returning with prey deposited the small nymphal grasshopper near the entrance,
removed the closure, entered, exited, and pulled the prey inside by its
antennae. This behavior was repeated several times per cell with one female
bringing five grasshoppers to her nest in 41 min. Larger prey were carried in a
series of short flights. Final closure involved the female pulling sand into the
burrow from the surface, with one wasp spending 54 min for this behavior. Individual
wasps remained with a single nest for up to five days.
Elliott (1996) excavated eight nests of T. similis on San Salvador Island.
The nests were one- and two-celled. Entrances were 4–5 mm in diameter.
Burrows were 3.5–9.5 cm long. Cells varied from 1 to 5 cm (mean = 2.3 ±
0.77, n = 10) in depth below the surface. Cells excavated in June were deeper
(mean = 3.4 ± 0.6 cm) than those dug in April (mean = 1.6 ± 0.1 cm). One cell
was 12 mm long. Completed cells contained two to seven (mean = 4.5 ± 1.0)
prey. Twelve of 15 grasshoppers in the cells were placed head inward and
ventral or dorsal side upward or on the side. The egg was positioned between
the bases of the fore- and middle legs of the prey. Wasps captured with prey
were 7–9 mm (mean = 8.1 ± 0.4) long, and the grasshoppers were 7–10 mm
(mean = 8.4 ± 0.5) in length. The nymphal Acrididae were not identified.
Wasps were occasionally pursued to their nests by unidentified satellite-flies,
and they responded with counter-cleptoparasitic behavior.
Kurczewski (2000) reported on 6 two-celled and 2 three-celled nests of T.
similis from Brunswick and Onslow Counties, NC. Both nesting sites were
comprised of moist, level sand. Females began excavating burrows as early
as 0934 (EDT) at a sand surface temperature of 36 ºC. They hunted at sand
surface temperature as low as 31 ºC and provisioned nests at sand surface
temperature as high as 55 ºC. Eighteen fully provisioned cells were unearthed
at an average depth of 28.6 mm (range = 14–36) below the surface.
Two of the cells were 6 mm high and 12–13 mm long. Cells held an average
of 5.5 (range = 3–8, n = 18) nymphal acridids identified as Melanoplus
femurrubrum (51 examples), Schistocerca sp. (1), Orphulella pelidna (19),
Dichromorpha viridis (26), Dissosteira carolina (1), and Arphia sp. (1).
Grasshoppers were put in the cells head inward and ventral or dorsal side
upward or on the side. The mean prey weight was 15.8 mg (range = 4–27,
n = 99). Aggregate prey weights of two cells were 44 and 82 mg. One wasp
weighed 12 mg. Wasp eggs, <2 mm long, were attached to the left (7) or right
(11) forecoxal coria of the prey.
H.E. Evans’ field note
Initially identified as T. terminatus (det. R.M. Bohart), field note CSL
478 from the “Little Gobi Desert,” Pottawatomie County, KS (July 1, 1953)
2009 F.E. Kurczewski 45
pertains to the red-tipped abdomen color form of T. similis. The female landed
with prey, removed the sand fill, took in the grasshopper, came out 30 sec later,
and re-made the entrance closure. She brought in five additional grasshoppers
at intervals of 8–25 min, then remained inside the burrow for 15 min, evidently
making a final closure. The nest was two-celled, with the cells only 1–2 inches
beneath the surface. The burrows were 2–2½ inches long. The two cells contained
six and seven “tiny” unidentified acridid nymphs. The cell with six prey
had the wasp’s egg attached to one of the grasshoppers.
Field studies
Nest location. Tachysphex similis nested in bare or sparsely vegetated,
dry to moist, loose to compact fine gravel, sand, or loamy fine sand (Table 6).
Most sites occupied level ground, but some nesting areas sloped as much
as 20–45° with the horizon. All sites were surrounded or bordered by vegetation.
Some nesting areas were modified substantially by human activity
(Table 7). Five rather large aggregations (TX-4, 7, 55, 67, 98) had 50–75
wasps nesting simultaneously (Table 7). Tachysphex similis and T. terminatus
occurred together in mixed aggregations at 17 locations, but some of the
sites were not assigned code numbers because of small wasp numbers and
minimal information.
Soils. Females nested in white, gray, tan, or brown fine gravel, coarse
sand, medium sand, fine sand, and loamy fine sand based on an analysis of
soils from all nesting sites (six of which are described in Table 6). Color
designation, hue, value, and chroma were not as important as soil particle
size in nesting-site soil characterization (Table 6).
Activity conditions. Females in eastern Kansas nested from May 7
(1966) to October 13 (1965). In southern Florida, females nested from
February through November (R.C. Miller, College of Environmental Science
and Forestry, Syracuse, NY, 1973 pers. comm.). Wasps were most
active on bright, sunny days when the air temperature in the shade was
Table 6. Soil characteristics at some Tachysphex similis nesting sites.
Site Soil particle size (%) Value/
No.1 Fg2 Cs3 Ms4 Fs5 Color Hue Chroma
TX-4 0.9 33.0 43.2 22.9 Gray 10 YR 5/1
TX-7 17.0 53.5 24.4 5.1 Light brown 7.5 YR 6/4
TX-636 55.1 40.7 3.1 1.1 Reddish yellow 7.5 YR 6/6
TX-677 9.7 60.0 23.6 6.7 Brown - -
TX-768 0.2 2.5 33.9 63.4 Pale brown 10 YR 6/3
TX-94 0.6 4.7 39.8 54.9 Brown 10 YR 4/3
1Table 7 provides a key and brief description for TX- sites.
2Fine gravel.
3Coarse sand.
4Medium sand.
5Fine sand + silt/clay.
6Same site as TX-54 (T. terminatus) listed in Table 1.
7Same site as TX-56 (T. terminatus) listed in Table 1.
8Same site as TX-20 (T. terminatus) listed in Table 1.
46 Northeastern Naturalist Vol. 16, Monograph 3
27–33 ºC. As soon as it clouded over, females stopped all nesting activities.
In Florida, wasps reopened the previous day’s burrow or exited recently
excavated burrows in which they spent the night as early as 0825–0835
(EST). At one locality (TX-41 [superscripts refer to generations: 1= spring,
2 = summer]), five males appeared on the surface at a sand surface temperature
of 28 ºC, 12 min before the first female (29 ºC). The next day at
the same locality, two females issued from their burrows at a sand surface
Table 7. Tachysphex similis site code numbers, site locations, site descriptions, and inclusive
dates of observation.
Inclusive dates
Site No. Site location Site description of collection
TX-3 Lake Annie, flSand ridge 27–28 Jun 1962
TX-4 1 km W Arcadia, flSand flats 1–2 Jul 1962,
25 Mar-4 Apr 1963,
26–30 Mar 1965,
5–8 Apr 1966,
31 Mar, 27–30 Jun 1967,
26–29 Mar 1968,
12–14 Mar 1986
TX-6 Palmdale, flSandy RR embankment 5–6 Jul 1962
TX-7 Archbold Biological Sand pile, sandy fire trail 6–7 Jul 1962,
Station, fl27–30 Mar 1963,
9 Apr 1966,
27 Mar-2 Apr,
25 Jun-4 Jul 1967
27 Jun 1968
TX-16 Lakeport, flSandy field 29 Mar–3 Apr 1963
TX-32 6 km N Geneva, NY Sandblow 7–9 Jul 1963
TX-40 Vincentown, NJ Sandy field 11–12 Aug 1963
TX-43 Colonie, NY Sand barren 17–18 Aug 1963,
20 Jun 1968
TX-55 8 km E Manhattan, KS Sandy draw 21 May–10 Jul 1965
TX-58 Blackjack Creek, KS Sandbank 31 May 1965
TX-61 Abilene, KS Sandy field 12 Jun 1965
TX-63 6 km SE Lecompton, KS Sandy RR embankment 28 Jun–8 Jul 1965
TX-66 Lakeview, KS Sandy lakeside 3 Jul–27 Aug 1965
TX-67 8 km NW Lawrence, KS Sand flats 28 Jul–19 Aug 1965,
6–31 May 1966
TX-76 2 km S Auburn, NY Sandpit 13–28 Aug 1968,
4 Aug 1969
TX-81 Presque Isle State Park, PA Sandy beach 19 Jul 1968,
9 Jul 1969
TX-82 6 km NW Chittenango, NY Sandy field 12 Jun 1969
TX-87 2 km SE Erie, PA Gravel pit 6 Aug 1967, 29 Aug 1983,
4–11 Jun 1986
TX-94 Selkirk Shores State Park, NY Sandpit 28-29 Jun 1972
TX-96 Allegan State Game Area, MI Sandy trail 10 Jun 1992,
11–13 Jun 1993
TX-98 Canadian Forces Base Sandy trail 27 Jun–27 Jul 1996,
Borden, ON 13 Jul 1997
TX-100 Cape Henlopen State Sandy parking lot 10-12 Jun 2005
Park, DE
2009 F.E. Kurczewski 47
temperature of 28 ºC and a cell-depth temperature of 20 ºC. Both wasps sat
in the sun “warming up” for 30 min before they started hunting. Females
were observed hunting and bringing prey to nests as early as 0850 at a sand
surface temperature of 32 ºC. Burrow excavation occurred as early as 0910
at a sand surface temperature of 32 ºC. Wasps in Florida brought prey to
nests and made temporary closures at sand surface temperatures as high as
62ºC and 63 ºC, respectively. They suspended their provisioning activities
at sand surface temperatures of 64–65°, staying inside their burrows until
the surface temperature decreased to 60–61 ºC, when the wasps resumed
provisioning. The females nested until 1820 (EST).
Emergence. First-generation females at one site in Kansas (TX-67) began
emerging on May 6, 1966. Recently emerged wasps were collected, frozen,
and weighed throughout May. Red-tipped females weighed, on average,
9.7 ± 1.6 mg (range = 8–13, n = 10) while all-black females weighed, on
average, 10.7 ± 1.9 mg (range = 8–14, n = 12). Females of both color variants
combined weighed, on average, 10.2 ± 1.8 mg (range = 8–14, n = 22).
There was slight correlation between date of emergence and size (weight) of
first-generation wasps (r = 0.4145), skewed by the fact that the first four and
seven of the first 10 emergent females at the site were red-tipped.
Burrow excavation. Females searching for nesting sites started burrows
as described under T. terminatus. They walked zigzag on the sand, tapped
their antenna tips on the surface, sampled the soil with their mandibles, and
used their forelegs in unison to remove the loose sand. If unsuccessful in
finding a suitable place to dig, wasps made low rapid flights to new areas and
resumed searching. Thirteen females each made several false starts 10–30
cm apart. They abandoned such excavations after 0.5–3.5 min, the burrows
being only 3–6 mm long. When abandoning a dig, a female paused, and flew
off (n = 7) or she turned and flung sand into the opening with her forelegs
for 4–6 sec before leaving (n = 6).
Not all females dug trial excavations before completing a burrow. Some
wasps remained where they started digging and finished a burrow. Eight females
stayed in one place and completed burrows in level sand. Some wasps
beginning burrows made brief interspersed hovering flights up to 8 cm high
above the site. They turned around once or twice in mid-air and landed facing
the entrance before resuming excavation.
A wasp loosened the sand surface with her mandibles. She then used her
forelegs in unison to rake the loose soil backward beneath her synchronously
lifting abdomen. Tachysphex similis moved their forelegs about twice as
fast as T. terminatus and much faster than T. apicalis at the same sand temperature.
Their mid- and hindlegs were used only for support and walking
in the burrow and entrance. Their antennae were bowed downward, the tips
constantly tapping the soil. Their wings were held flat on the dorsum.
Females backed from their excavations at intervals to remove the loose
sand that accumulated in the burrows and entrances. This action was accomplished
by throwing the sand backward with their forelegs beneath
48 Northeastern Naturalist Vol. 16, Monograph 3
their synchronously lifting abdomen. The intervals at which the wasps removed
sand from their burrows and entrances, as measured by the duration
they were inside and out of sight, usually lengthened as they dug deeper
(Fig. 23). The irregular pattern in mean values in Figures 23, 24, and 26 is
related to fewer than 10 observations per sand-removal set, considerable
variation in the number of burrow entries to obtain sand, and the uneven
duration of burrow excavations.
Females removing sand from burrows usually backed half the distance
of the surface accumulation or farther when clearing it from in front
of an entrance. Some wasps removed the loose sand to the edge of the
accumulation, 45–65 mm from their entrances. Four females raking loose
sand backward went beyond the accumulation, backing as far as 75–142 mm
from the entrances. The distance to which the wasps removed sand from the
entrances increased as the excavation proceeded (Fig. 24).
Seventeen females began to extensively level the loose sand in front of an
entrance following 19–62 sand removal episodes, 8–45 min after starting. This
leveling consisted of throwing sand backward with their forelegs as described
above. Most females moved laterally or diagonally while smoothing the sand
accumulation in front of an entrance. The leveling paths were similar to those
of T. terminatus (Fig. 25). The leveling paths increased in complexity and
the duration spent smoothing the accumulation lengthened as an excavation
proceeded to completion (Fig. 26). Some wasps spent from 1 to 6.5 min for
an individual leveling session following a sand removal episode. One female
Figure 23. Mean interval (in seconds) between successive trips backward to remove
sand during burrow excavation plotted against sand removal number in Tachysphex
similis (bar graph averages in sets of five with standard error bars; TX-4, 7, 55, 63, 66).
2009 F.E. Kurczewski 49
(TX-71) spent 35 min leveling the sand surface near her entrance and only 15
min excavating inside her burrow. Only one of 17 (5.9%) females made no attempt
to level the sand accumulation in front of her entrance. She left a sand
deposit, 20 mm wide x 36 mm long x 4 mm high, in front of the entrance.
Some wasps interrupted leveling the sand and made periodic hovering
flights up to 20–30 cm high during which they turned completely around in
mid-air and landed facing the entrance. Such flights may have familiarized
the females with their surroundings to facilitate finding the entrance upon
Figure 25. Leveling path for single
sand removal episode near end of
burrow excavation in Tachysphex
similis (TX-7). Dashed lines are
short, low flights.
Figure 24. Mean distance (mm) traveled to remove sand during burrow excavation
plotted against sand removal number in Tachysphex similis (bar graph averages in
sets of five with standard error bars; TX-4, 7, 55, 63, 66).
50 Northeastern Naturalist Vol. 16, Monograph 3
subsequent returns with prey. Wasps also flew to and rested on vegetation
between leveling sessions.
Females spent considerable time on the surface, throwing sand back toward
the entrance near the end of an excavation. This sand was subsequently
used in making the temporary closure. Wasps often stopped flinging sand
backward, walked to the entrance, and examined the fill up to 22 times per
excavation. Antenna cleaning following a sand removal episode occurred up
to three times per excavation.
The last or last few intervals spent inside the burrow were considerably
longer in duration than prior intervals and apparently represented the
shaping of a cell. This duration amounted to 3.3–8.5 min (mean = 5.3 ± 1.9,
n = 13). Moist sand was pushed into the entrance from below, plugging the
opening and signaling this event.
After making the cell, a female appeared headfirst in her entrance and
began her temporary closure. Keeping her wings flat on her dorsum, she
flung sand backward into the opening using her forelegs in unison for 3–12
sec (mean = 5.4 ± 3.1, n = 18) at various sand surface temperatures. A few
females used their mandibles and end of abdomen, along with their forelegs,
in temporarily closing the entrance. Some wasps remained at the far edge
of their depressed entrance with head bowed downward and did not move
onto the surface during temporary closure. Other females proceeded as far
as 10 mm from the opening while throwing sand into it. Some closures were
filled flush with the surrounding sand. But, most closures remained 1–3 mm
depressed after the wasps departed. Females made circular orientation flights
Figure 26. Mean duration (in seconds) spent on surface distributing sand removed
from burrow excavation plotted against sand removal number in Tachysphex similis
(bar graph averages in sets of five with standard error bars; TX-4, 7, 55, 63, 66).
2009 F.E. Kurczewski 51
of increasingly larger radii above the area. The orientation flight of one wasp
increased from 6 to 30 cm in diameter, interspersed with 11 landings to face
the filled entrance.
Wasps made 23–67 (mean = 48.9 ± 14.6, n = 14) entries to remove sand from
the burrow and entrance during an excavation. The duration spent to dig the
main burrow and first cell averaged 38.6 ± 9.7 min (range = 18–57, n = 18).
Additional cells. Females often excavated a side burrow and second
cell in a nest after stocking the first cell with prey and ovipositing on a
grasshopper, followed by side burrows that led to third, fourth, and fifth
cells. The additional burrows and cells were usually dug off the main
burrow (Fig. 21). Most of the soil from a new dig was packed into the
previous burrow. It was transferred from the new burrow to the main burrow
below ground and out of sight. The wasp backed into her entrance
only occasionally when making the new burrow and cell. Orientation
flights following temporary closures of the entrances were rarely seen
and, if made, were brief in duration.
When making additional burrows and cells in a nest, females first backed
into entrances 3–14 min (mean = 8.6 ± 3.8, n = 8) after taking in the last prey
for the first cell. They removed sand from the new burrow and cell only 0–20
(mean = 6.8 ± 6.8, n = 10) times during an excavation. Six of eight wasps
spent lengthy (44–98 sec) individual intervals below ground about midway
or later through an excavation, probably moving loose sand from the new
burrow to the main burrow. One female did not remove any sand onto the
surface from the excavation of her second and third cells.
The maximal distance a wasp backed from her entrance when removing
the loose sand from the new excavation was only 12–27 mm (mean = 16.6
± 5.0, n = 8). There was no extensive leveling of the sand accumulation on
the surface in front of the entrances by females (n = 8) because there was so
little sand removed from the burrow. The last interval between consecutive
appearances in entrances to remove sand from the burrow was lengthy (mean
= 3.1 ± 1.5 min, range = 1.0–5.3, n = 6), apparently being used for shaping
the new cell at the end of the recently excavated side burrow.
Females exited the opening flinging sand backward with their forelegs in
unison beneath their synchronously lifting abdomen when making the temporary
closure. This closure took only 2–3 sec at sand surface temperatures
of 53–60 ºC (n = 6). Afterward, the entrance remained slightly depressed or
partly open at the top. Two wasps closed their entrances from within with
damp sand and remained inside following excavation of a new burrow and
cell. One female made two examinations of the fill and a brief orientation
flight following her temporary closure. Females spent 9–20 min (mean =
14.6 ± 3.3, n = 8) to excavate a new burrow and cell.
Females in Kansas (TX-671) completed up to five fully provisioned cells
per day in May, but only two per day in August (TX-632). Females in Florida
(TX-41, 71) completed up to three fully provisioned cells per day in late
March–April, but only two per day in late June–July (TX-42, 72).
52 Northeastern Naturalist Vol. 16, Monograph 3
Rain burrows. With an approaching rain, many females hurriedly excavated
a short simple burrow in the sand using their mandibles and forelegs
in unison. This burrow did not terminate in an ovoid cell. They closed
themselves inside such a burrow in a head outward position, plugging the
entrance with damp sand from below. One sand plug was 8 mm long. Two
rain burrows took 4 and 5 min to dig. The burrows were abandoned following
the rain, remaining wide open and fronted by a small mound of sand. Two
rain burrows in Florida (TX-42) were 39 and 31 mm long. They entered the
sand obliquely at about a 40° angle with the surface.
Hunting. After making an orientation flight, females often flew to a
nearby source of vegetation to hunt for prey. A few wasps searched for prey
on vegetation only 60–90 cm from their nests. Most females were observed
hunting 15–30 m from the bare sand in which they nested. They were able
to hunt many meters from their nests because the prey they captured were
relatively small in size and transported rather rapidly in flight.
Prey comprised mainly early nymphal stages of Acrididae found commonly
on grasses and decumbent and upright plants. Some females hunted
low to the ground, running rapidly on plants interspersed with hovering
flights. Other wasps made rapid flights, 6–12 cm long, from plant to plant,
walked slowly on the stems and leaves with their wings held flat on their
dorsum, paused in certain places, and tapped their antennae, especially at the
petioles of plants with compound leaves. Some females stopped and rested
with their antennae held rigidly upward.
If unsuccessful in locating suitable prey, females interrupted hunting
activities and returned periodically in flight to their nests. Such returns were
made from a few minutes to 4.5 hours apart. Females landed in front of
their entrances, sometimes examined the fill, turned, and flew off, or they
removed the temporary closure, entered, exited a few seconds later, re-made
the closure, and flew away. Wasps returned empty-handed up to five times
between bringing consecutive prey items to their nests.
Seven wasps captured grasshoppers at distances of 3–4 m from their
nests. Prey capture was preceded by hovering flights that turned into lightning-
fast forward flights, 6–12 cm long, once a grasshopper was located.
One female caught a Melanoplus sp., 3 mm long, on vegetation, flew to the
ground, stung it in the right side of the ventral thorax for 2 sec, dismounted,
cleaned her antennae, legs, and abdomen, remounted the prey, and stung it
in the other side for 1 sec. She repositioned the grasshopper ventral side upward,
climbed atop it, grasped the bases of its antennae with her mandibles
and its body with her legs, and took flight. A second wasp stung a different
Melanoplus sp., 4 mm long, in the left side of the thorax for 3 sec, turned the
prey over, kneaded the base of its left foreleg with her mandibles for 6 sec,
and flew away holding it underneath. A third female stung her prey in the
left side of the ventral thorax for 4 sec, then kneaded the base of the foreleg
on that side for 9 sec, grasped it ventral side upward, and flew off. This wasp
returned to the same plant in <2 min, hovered next to a leaf, pulled a prey
off the plant in <1 sec, flew to the ground with it, stung it for 4 sec, cleaned
2009 F.E. Kurczewski 53
herself for 7 sec, rested, grasped it as described above, and flew away. One
female that had been repeatedly capturing species of Gomphocerinae stung
a slightly larger oedipodine grasshopper. However, she abandoned this prey
on the sand surface and flew away.
Prey transport. The mean ratio of weight of prey to wasp observed in
flight transport was 0.6:1 (range = 0.22–2.01, n = 197). Only a single grasshopper
weighing 30 mg (wasp 14 mg, ratio 2.14:1) was carried to a nest on
the ground. Five other prey weighing 31–45 mg (wasps 15–20 mg, ratios
2.06–2.58:1) were transported in low flights, 15–30 cm long, interspersed
with ground transport. During the tail-heavy flights, the grasshopper’s abdomen
projected beyond that of the wasp and its hindlegs dangled downward.
The wasp’s wings produced a clearly audible, low-pitched buzzing sound.
Such females rested often on the sand surface and low plants.
All but one grasshopper was carried headfirst and ventral side upward,
being held around the body with the legs and by the bases of the antennae
with the mandibles (Fig. 27). One prey was carried headfirst and dorsal side
upward. Most flights were made directly to the nests. Some wasps interrupted
flights to land and pause momentarily on soil or vegetation before
resuming transport to their nests. During pauses, they released the grasshopper
as described for T. terminatus and, rarely, kneaded the prey's forecoxal
corium with their mandibles.
In Kansas, first-generation (May–June) wasps (TX-55, 1965) spent
significantly less time between consecutive prey items than second- and
later-generation (July–August) wasps from another site (TX-66, 1965):
Figure 27. Female Tachysphex similis resting on sand following lengthy flight transport
(TX-7). Wasp grasps bases of grasshopper’s antennae with her mandibles and,
in flight, holds prey’s body with her legs.
54 Northeastern Naturalist Vol. 16, Monograph 3
mean = 6.5 ± 5.9 min, range = 1–33, n = 154 vs. mean = 11.2 ± 9.0 min,
range = 2–38, n = 33 (P = 0.0084). One wasp provisioning in the morning in
Florida (TX-71, 1963) spent an average of 34.9 ± 34.7 min (range = 8–109,
n = 7) between successive prey items.
Nest entry. Provisioning females landed on the sand and placed the grasshopper
ventral side upward or on its side with its head near the entrance. More
than 100 prey were placed with the head 4–21 mm, usually 7–9 mm, from the
opening. A grasshopper was nearly always put in front of the entrance in a
straight line with the direction of the burrow. Prey were not placed above
the entrance or beside it on the left or right at right angles to the direction of
the burrow. After releasing the grasshopper on the sand, four of 979 (0.4%)
observations in Florida and Kansas at sand surface temperatures of 58–61 ºC
indicated a single, very brief, low hovering flight prior to nest entry.
Prior to entry, wasps tapped their antenna tips alternately on or held them
against the fill. Upon locating the closure, they removed the sand fill using
their forelegs simultaneously (Fig. 28). The sand was flung backward with
the forelegs in unison as the abdomen lifted synchronously. A few females,
after releasing their prey on the sand surface, lost track of the temporary
closure, dug in several places surrounding the entrance, but never found their
nest. Such wasps abandoned the prey on the surface and began a new burrow
elsewhere. The relatively loose and often depressed closure of this species
may function in helping females find their nest entrances as well as provide
rapid entry on the hot sand.
After releasing the prey and removing the sand fill, a female entered her
burrow headfirst, turned around inside (Fig. 29), walked up the burrow, and
Figure 28. Female Tachysphex similis has released a paralyzed grasshopper on the sand
surface and begins to remove the temporary closure using her forelegs in unison (TX-7).
2009 F.E. Kurczewski 55
appeared in the entrance headfirst in 2–9 sec (mean = 3.3 ± 1.7, n = 730).
A wasp walked to her prey, grasped it by the end of an antenna and walked
backward into the burrow pulling it behind (Fig. 30). If in the early or
middle stages of provisioning, she reappeared headfirst, temporarily filled
Figure 30. Female Tachysphex similis grasps a grasshopper by an antenna with her
mandibles and begins dragging it backward into her burrow (TX-7).
Figure 29. Female Tachysphex similis is inside her burrow. A paralyzed grasshopper
lies on the sand surface (TX-7).
56 Northeastern Naturalist Vol. 16, Monograph 3
the entrance with loose sand (Fig. 31), and flew off to obtain additional prey.
The removal of temporary closure, entry, exit, re-entry with prey, exit, and
new temporary closure averaged about 18 sec including 3–16 sec (mean =
6.7 ± 3.4, n = 662) to deposit the grasshopper in the cell.
Most wasps did not proceed far from the opening when closing their
entrances. They bowed their head downward and flung sand backward
with their forelegs, staying mostly in the depressed area of the entrance.
The mainly filled area often remained depressed 1–3 mm after the female
flew away.
Some wasps provisioned continually from mid-morning to late afternoon
regardless of sand surface temperature. Eight Kansas females (TX-67)
consecutively brought 13–33 grasshoppers to nests in 1.5–5 hours at sand
surface temperatures ranging from 38 to 61 ºC. Four Florida females (TX-4)
consecutively arrived at nests with 5–18 prey in 3–6 hours at sand surface
temperatures ranging from 35 to 63 ºC. The cumulative hours per female did
not include duration spent excavating additional burrows and cells in nests.
The removal of the temporary closure prior to nest entry and temporary
closure were made increasingly faster in a straight-line relationship as sand
surface temperature rose from 35 to 60 ºC (Figs. 32, 33). There was essentially
no significant difference in temporary closure removal or temporary
closure rates of activity or duration between Kansas and Florida wasps
(Figs. 32, 33). Wasps left entrances incrementally more open as they spent
less time making the closures at higher sand surface temperatures (58–63 ºC).
Final closure. Before filling a burrow, some females exited their
entrances, made a few short flights around the area, rested briefly on the
Figure 31. Female Tachysphex similis makes a temporary closure, using her forelegs
in unison, after placing a grasshopper in the nest (TX-7).
2009 F.E. Kurczewski 57
surface, re-entered their burrows headfirst, came back out, turned around,
reentered again, and began closing. A wasp began filling the burrow by
breaking down the top and sides with her mandibles, twisting her head from
Figure 32. Mean duration of temporary closure removal (in seconds) plotted against
sand surface temperature (in degrees C) in Tachysphex similis (TX-4, 7, 55, 61, 63,
66, 67).
Figure 33. Mean duration of temporary closure (in seconds) plotted against sand surface
temperature (in degrees C) in Tachysphex similis (TX-4, 7, 55, 61, 63, 66, 67).
58 Northeastern Naturalist Vol. 16, Monograph 3
left to right and vice versa. The loose soil was thrown backward beneath her
synchronously lifting abdomen, using her forelegs in unison. Falling at the
end of the burrow in front of the cell, the loose sand was tamped rapidly into
place with the bent end of the abdomen. One wasp atypically entered her
burrow headfirst during 13 of 19 exits to retrieve sand for the fill.
As a female increasingly filled her burrow with sand, she eventually appeared
in the entrance 2.5–24 min (mean = 8.9 ± 8.4, n = 13) after taking in
the last prey and ovipositing. As she walked onto the surface, her forelegs
continuously raked sand backward into the opening beneath her synchronously
lifting abdomen. Her wings were held flat on her dorsum. Staying
outside at first only a second or two, she backed quickly into the burrow
with sand. She spent increasingly longer periods of time on the surface
to obtain sand as the closure went to completion (Fig. 34). Females came
out of their burrows increasingly farther to get loose sand as the supplies
near the entrances were depleted (Fig. 35). As a burrow filled with sand,
the intervals at which the wasp came out to get additional soil gradually
decreased in duration (Fig. 36). One wasp nesting on a slope turned around
and, standing on hindlegs, broke down the burrow walls and entrance using
mainly her mandibles.
Antenna cleaning was not observed during 13 final closures. One wasp
made a hovering flight above the area, turned around in mid-air, landed facing
the entrance, turned away, and backed into the burrow raking sand backward.
After filling the burrow, females spent 1.0–3.5 min smoothing the sand surface
Figure 34. Mean duration (in seconds) spent on surface raking sand backward into
burrow for final closure plotted against sand retrieval number in Tachysphex similis
(bar graph averages in sets of five with standard error bars; TX-4, 7, 55, 61, 63, 66).
2009 F.E. Kurczewski 59
in front of an entrance. They periodically interrupted this behavior and walked
across the sand to examine the fill 0–28 (mean = 14.4 ± 14.4, n = 10) times
Figure 36. Mean interval (in seconds) between successive exits to obtain sand for
final closure plotted against sand retrieval number in Tachysphex similis (bar graph
averages in sets of five with standard error bars; TX-4, 7, 55, 61, 63, 66).
Figure 35. Mean distance (mm) to which wasps walked to get loose sand for final
closure plotted against sand retrieval number in Tachysphex similis (bar graph averages
in sets of five with standard error bars; TX-4, 7, 55, 61, 63, 66).
60 Northeastern Naturalist Vol. 16, Monograph 3
during closure. Wasps made 9–23 trips (mean = 16.6 ± 5.1, n = 10) onto the
surface to obtain sand for the fill. The amount of time spent filling the burrow
and distributing sand atop the entrance before departing was 6–115 min (mean
= 17.0 ± 32.1, n = 11).
Two wasps in Florida (TX-42, 72) spent 105 and 120 min, respectively, to
excavate, provision, oviposit on a prey, and close 2 one-celled nests.
Nest structure and dimensions. Females dug short shallow burrows that
entered the sand obliquely at angles of 21–46° with the surface. Thirty of
50 (60.0%) burrows penetrated the soil at lateral curvatures of greater than
22.5° (Fig. 21). Some burrows were nearly circular in configuration. Nests
were one- to five-celled with three-celled nests being prevalent (Fig. 21).
Burrows leading to second cells left the main burrows at distances of 17–84
mm (mean = 40.3 ± 21.1, n = 17) from the entrances. Burrows leading to
third cells left the main burrows at distances of 10–66 mm (mean = 31.3 ±
21.8, n = 6) from the entrances. Distances between first and second cells
Table 8. Burrow length and cell depth in Tachysphex similis nests.3
Site Burrow length (mm) Cell depth (mm)
TX-year4 N Range Mean ± SD N Range Mean ± SD
32 1 63 63.0 1 28 28.0
42-1962 3 50-62 57.3 ± 6.43 3 30-32 31.0 ± 1.00
41-1963 2 79-95 87.0 ± 11.31 2 45-49 47.0 ± 2.83
41-1965 9 97-128 107.3 ± 10.76 9 49-67 60.9 ± 6.21
41-1966 6 81-99 89.8 ± 6.71 6 49-58 53.0 ± 3.10
42-1967 1 114 114.0 1 59 59.0
41-1968 8 85-107 95.4 ± 7.52 8 39-54 46.9 ± 5.00
62 1 100 100.0 2 45-65 55.0 ± 14.14
72-1962 1 75 75.0 1 34 34.0
71-1963 5 49-79 67.6 ± 11.39 5 37-52 42.8 ± 6.26
72-1967 6 59-73 67.2 ± 5.81 6 34-53 40.5 ± 6.89
72-1968 1 71 71.0 1 36 36.0
161 5 63-88 74.6 ± 9.86 5 45-58 50.8 ± 5.36
402 5 48-71 63.4 ± 9.24 5 27-34 30.8 ± 3.11
432 3 53-62 58.0 ± 4.58 3 31-41 37.3 ± 5.51
551 15 44-83 64.1 ± 12.98 15 16-37 27.1 ± 5.51
581 3 90-112 100.0 ± 11.14 3 37-39 37.7 ± 1.15
611 1 42 42.0 1 21 21.0
632 5 44-83 63.0 ± 15.28 5 17-47 34.8 ± 15.37
662 1 39 39.0 1 15 15.0
672-1965 2 43-55 49.0 ± 8.49 2 18-21 19.5 ± 2.12
671-1966 8 57-84 69.5 ± 8.65 14 25-49 33.6 ± 6.42
812 1 60 60.0 1 30 30.0
821 2 75-83 79.0 ± 5.66 2 37-38 37.5 ± 0.71
941 2 48-55 51.5 ± 4.95 2 18-20 19.0 ± 1.41
961 3 41-61 52.0 ± 10.15 3 22-25 23.3 ± 1.53
981 3 45-55 51.7 ± 5.77 3 28-34 30.7 ± 3.06
1001 3 58-63 60.3 ± 2.52 3 26-29 27.7 ± 1.53
1Spring generation.
2Summer generation(s).
3Includes cell length and cell height, respectively.
4Table 7 provides a key and brief description for TX- sites.
2009 F.E. Kurczewski 61
were 9–65 mm (mean = 39.6 ± 24.2, n = 16) and between second and third
cells were 8–56 mm (mean = 34.2 ± 12.9, n = 9).
Burrow diameters were 3–6 mm, enlarging to 4–6 mm at the entrances.
Each burrow ended in a somewhat declined cell or short spur. The cells were
oval to elongate oval in shape. Cell height, width, and length were similar at
all localities. Fifty-one of 55 (92.7%) cells measured 5–8 mm high, 6–9 mm
wide, and 9–12 mm long.
Longer and deeper spring nests and shorter and shallower summer nests
were the norms at several Florida and Kansas sites (Table 8). Florida cells
were significantly deeper than Kansas cells throughout the nesting season:
Florida mean = 47.6 mm, Kansas mean = 29.8 mm; t = 8.5796, P < 0.0001, df
= 57 (Fig. 37). There was no correlation between wasp size (weight) and cell
depth in Kansas (r = 0.0312) or Florida (r = -0.0584) when the two samples
were separated. However, when the two samples from the different regions
were combined, the correlation was much stronger (r = 0.5365; Fig. 37).
Prey. Prey consisted entirely of small nymphal Acrididae. Overall, the
wasps were rather unselective of their prey, capturing 14 genera and 24 species
based on 812 specimens (Table 9). Several hundred specimens remain
unidentified, so that number is probably on the low side. The prey subfamilies
consisted of Cyrtacanthacridinae + Melanoplinae, (581 specimens,
71.6%), Gomphocerinae (122, 15.0%), and Oedipodinae (109, 13.4%). As
many as three subfamilies, genera, and species of Acrididae were found in a
single cell.
Prey species differences associated with different generations of wasps
were not evident in Florida, as the females nested throughout much of the year
Figure 37. Weight (mg) of female Tachysphex similis plotted against cell depth (mm)
in Kansas (TX-55, 58, 61, 63, 66, 67) and Florida (TX-4, 7).
62 Northeastern Naturalist Vol. 16, Monograph 3
and had access to many of the same species of grasshoppers, more or less,
year-round. Most prey from Kansas were from first-generation (May–June)
nests, making a comparison with prey from later generations difficult to make.
The number of prey stocked in fully provisioned cells was 1–15
(Table 10). Most cells held three or more grasshoppers. First-generation
(spring) cells generally held more prey than later-generation (summer) cells
(Table 10). Some cells with only one or two prey were closed prematurely
at the onset of bad weather or dusk. In Kansas, first-generation all-black
females stocked 5–14 (mean = 8.7 ± 2.8, n = 15) grasshoppers per fully
provisioned cell while first-generation red-tipped abdomen females stocked
5–15 (mean = 8.9 ± 3.3, n = 16) prey per fully provisioned cell, an insignifi-
cant difference.
The contents of early summer, fully provisioned cells from one location
in Florida (TX-72 [1967, 1968]) with only one or two prey may have resulted
from scarcity of grasshoppers of suitable size and quasi-droughty conditions.
Only 196 mm of rain fell between January 1 and June 1, 1967 compared to
the normal average amount of 357 mm at that location. The site received
only five days of rainfall totaling 67 mm in April and May 1967. Two wasps
each spent nearly three days between successful provisioning trips. Several
days of net-sweeping around the nesting area indicated a paucity of nymphal
Acrididae of appropriate prey size.
Table 9. Species of prey of Tachysphex similis, listed in alphabetical order.
Species of prey (nymphs) No. specimens
Achurum carinatum (Walker) 10
Amblytropidia mysteca (Saussure) 4
Aptenopedes sphenarioides Scudder 48
Arphia granulata Saussure 65
Arphia simplex Scudder 32
Arphia xanthoptera (Burmeister) 1
Chloealtis conspersa (Harris) 12
Chorthippus curtipennis (Harris) 6
Dissosteira carolina (Linnaeus) 2
Melanoplus bivittatus (Say) 2
Melanoplus differentialis (Thomas) 77
Melanoplus femurrubrum (DeGeer) 32
Melanoplus keeleri (Thomas) 30
Melanoplus puer group 43
Melanoplus s. sanguinipes (Fabricius) 64
Melanoplus sanguinipes vulturnus Gurney and Brooks 43
Melanoplus seminole Hubbell 18
Melanoplus viridipes Scudder 5
Melanoplus spp. 164
Melanoplinae, unknown genus 21
Orphulella pelidna (Burmeister) 58
Psinidia fenestralis (Serville) 17
Schistocerca americana (Drury) 35
Spharagemon marmorata picta (Scudder) 6
Syrbula admirabilis (Uhler) 17
2009 F.E. Kurczewski 63
In multi-celled nests with fully provisioned cells, cell 1 usually contained
more prey (mean = 10.0 ± 3.3, range = 2–14, n = 33) than cell 2 (mean = 6.0
± 2.7, range = 1–12, n = 27) or cell 3 (mean = 5.4 ± 2.6, range = 3–10, n = 8).
One fully provisioned cell 4 held 15 grasshoppers.
Most of the grasshoppers stocked in the cells were the same size and weight
or smaller and lighter in weight than the wasps. Prey individuals ranged from
3.0 mm (Melanoplus sp.) to 11.5 mm (Aptenopedes sphenarioides, Achurum
carinatum) in body length. Florida prey weighed significantly less in spring
(March–April mean = 8.9 ± 5.6 mg, range = 2–31, n = 174) than in early
summer (late June–July mean = 19.6 ± 11.8 mg, range = 6–45, n = 38) (P <
0.001). In Kansas, prey of the spring generation weighed, on average, only
about half as much as prey from mid- to late summer (May–June mean =
6.4 ± 3.2 mg, range = 3–21, n = 250 vs. July–August mean = 11.6 ± 6.8 mg,
range = 3–31, n = 31) (P < 0.05).
Table 10. Number of prey and aggregate prey weight per cell in Tachysphex similis nests.
Site No. prey per cell Aggregate prey wt. (mg)
TX-year3 n Range Mean±SD n Range Mean±SD
32 1 3 3.0
42-1962 1 3 3.0
41-1965 7 2–8 5.3 ± 2.21 7 26–102 53.7 ± 28.16
41-1966 15 2–12 6.4 ± 2.85 10 31–71 49.3 ± 12.50
42-1967 8 3–10 7.0 ± 2.48 1 75 75.0
41-1968 6 6–11 8.0 ± 2.27
41-1986 5 2–7 4.2 ± 2.17 5 20–67 41.8 ± 20.78
62 1 9 9.0
72-1962 1 3 3.0
71-1963 4 5–13 9.2 ± 4.35 4 34–98 67.8 ± 33.98
71-1967 22 3–10 6.4 ± 2.34
72-1967 6 1–2 1.67 ± 0.52 6 31–80 51.8 ± 20.72
72-1968 1 1 1.0 1 42 42.0
161 4 3–9 5.0 ± 2.71 4 33–77 52.3 ± 21.31
402 4 2–5 3.0 ± 1.41
432 1 5 5.0
551 12 5–14 7.9 ± 2.86 12 29–74 52.8 ± 16.65
581 3 5–11 8.7 ± 3.21 3 46–85 64.0 ± 19.67
611 1 5 5.0 1 29 29.0
632 5 4–5 4.4 ± 0.55 5 28–82 48.0 ± 21.01
662 4 3–8 5.3 ± 2.22 1 41 41.0
672-1965 1 5 5.0 1 37 37.0
671-1966 15 5–15 9.1 ± 3.20 12 32–91 56.9 ± 19.76
812 1 3 3.0 1 29 29.0
821 2 8–9 8.5 ± 0.71 2 37–49 43.0 ± 8.48
871 4 6–8 7.0 ± 0.82
941 2 8 8.0 2 42–51 46.5 ± 6.36
961 2 4 4.0 2 53–62 57.5 ± 6.36
981 2 5 5.0 2 56–83 69.5 ± 19.09
1001 3 5–7 6.0 ± 1.00 3 45–65 58.0 ± 11.27
1Spring generation.
2Summer generation(s).
3Table 7 provides a key and brief description for TX- sites.
64 Northeastern Naturalist Vol. 16, Monograph 3
The aggregate prey weight of cells from the various sites in presented
in Table 10. Cells with higher aggregate prey weight probably produced
larger female wasps while those with lower aggregate prey weight probably
produced smaller male wasps, although this was not proven during the study.
The cell contents of first-generation all-black females in Kansas had an aggregate
prey weight of 29–91 mg (mean = 57.7 ± 18.7, n = 15), while that
of first-generation red-tipped abdomen females in Kansas had an aggregate
prey weight of 29–85 mg (mean = 51.6 ± 18.2, n = 13).
In multi-celled nests with fully provisioned cells, cell 1 had a higher aggregate
prey weight (mean = 59.3 ± 19.5 mg, range = 28–102, n = 25) than
cell 2 (mean = 40.1 ± 10.7 mg, range = 26–61, n = 19) or cell 3 (mean = 45.8
± 11.5 mg, range = 33–66, n = 6). A decrease in the aggregate prey weight
per fully provisioned cell from spring to mid-summer was evident at a few
sites (Table 10).
Nesting wasps weighed 8–20 mg (mean = 12.5 ± 3.5, n = 77). Florida
females were significantly heavier (mean = 15.7 ± 3.3 mg, range = 10–20,
n = 28) than Kansas females (mean = 10.3 ± 1.7 mg, range = 8–14, n = 38)
(t = 7.8622, P < 0.0001, df = 38; Fig. 37). Kansas females included all-black
individuals (mean = 10.7 ± 1.7 mg, range = 8–14, n = 22) from six locations
and wasps with a red abdominal apex (mean = 10.3 ± 1.7 mg, range = 8–13,
n = 16) from four sites (TX-55, 58, 61, 67). The slightly heavier weights of
the all-black females corresponded with the slightly higher cell aggregate
prey weights of this color variant (see above).
Three hundred fifty-eight of 450 (79.6%) prey were put in the cells in a
head inward and ventral side upward or on the side position. Eighty-three
(18.4%) grasshoppers were placed in the cells in a head inward and dorsal
side upward position. Five prey were put in the cells head outward and ventral
side upward, and four grasshoppers were put in head outward and dorsal
side upward. Grasshoppers in atypical positions may have been accidentally
moved by wasps maneuvering to oviposit on another prey in the cell.
Egg. A female usually laid her egg on a grasshopper placed toward the
bottom of the cell near the back end, especially where there were multiple
prey in the cell. The grasshopper to which the egg was affixed was positioned
head inward and ventral side upward in 167 of 180 (92.8%) cells. Eleven
eggs were attached to prey that were positioned head inward and dorsal side
upward and 2 to prey placed head outward and ventral side upward.
The grasshopper to which the egg was affixed was often the largest and
heaviest prey in the cell. Fifty-four of 90 (60.0%) eggs were laid on the
heaviest prey, 28 (31.1%) on the second heaviest, 4 on the third heaviest; 2
on the fourth heaviest, and 2 on the lightest grasshopper in the cell. Three
cells contained only a single prey. Eggs were attached to prey that weighed
3–44 mg (mean = 14.5 ± 9.5, n = 73). Other prey in the cells weighed
2–45 mg (mean = 7.1 ± 4.7, n = 274), a significant difference (P < 0.001).
Egg-bearing grasshoppers were the first (2 examples), second (2), or third
(3) individuals taken into entrances in seven of nine cells. Eggs were laid on
other sequential prey in two cells.
2009 F.E. Kurczewski 65
The wasp’s egg was affixed to the soft intersegmental membrane surrounding
the base of a forecoxa by the less tapered, distal end. The proximal
end extended free to the opposite side, the egg lying transversely across the
pro- and mesosterna between the bases of the fore- and midcoxae. Forty-six
(51.1%) eggs were attached to the intersegmental membrane surrounding
the base of a left forecoxa, and 44 (48.9%) eggs to the intersegmental membrane
surrounding the base of a right forecoxa. Fourteen of 24 (58.3%) eggs
in two-celled nests were affixed to the same (left or right) side of the prey’s
forecoxal intersegmental membrane, and nine of 18 (50.0%) eggs in threecelled
nests were attached to the same side of the grasshopper’s forecoxal
intersegmental membrane.
Live eggs were slightly curved, sausage-shaped, white or cream-colored,
and measured 1.5–1.9 mm (mean = 1.77 ± 0.15, n = 12) long and 0.4–0.5 mm
(mean = 0.43 ± 0.05, n = 12) wide.
Tachysphex apicalis apicalis
Literature review
Krombein (1964) located one nest of T. a. apicalis in a 60° sand slope in
Highlands County, fl. The female was bringing prey to her nest in flight,
entering the open burrow, and exiting a few seconds later. This nest was excavated
after the female began her final closure. The burrow went in “almost
horizontally, turned downward at a right angle,” and terminated in a cell
4 cm from the sloped surface. The cell held seven nymphal grasshoppers,
7–10 mm long, of two different instars of Melanoplus sp., possibly puer
(Scudder). The sausage-shaped egg, 2.2 mm long, was affixed on the left side
extending transversely across the sternum between the fore- and mid-coxae
of a “medium-sized” prey. Pulawski (1988) reported this species nesting in
vertical portions of land tortoise burrow entrances at the Archbold Biological
Station, fl.
Tachysphex a. apicalis was noted nesting in steep sand slopes and cliffs
in Florida (Kurczewski and Snyder 1968). Burrow excavation was begun
using the mandibles with assistance from the forelegs in unison following
penetration of the surface. Females did not temporarily close the entrance
with loose sand after completing a burrow and cell. They flew off and returned
in flight, often several times, with small grasshoppers. Most wasps
entered their burrows without pausing, holding the prey underneath with
their mandibles and legs. Some females, with larger grasshoppers, released
them just within the entrance and pulled them in from inside the burrow.
After finishing a nest, the female broke down the area of the entrance with
her mandibles and packed the loose soil in the burrow with the end of her
abdomen. Nests often contained several cells, with most cells each containing
several nymphal Acrididae.
Kurczewski (2000) located a three-celled nest of T. a. apicalis near the
top of a sandy incline in Bladen Lakes State Forest, Bladen County, NC. The
cells were unearthed at distances of 56, 62, and 73 mm, including cell length,
66 Northeastern Naturalist Vol. 16, Monograph 3
from the surface. They contained four, five, and seven small acridid nymphs
identified as Melanoplus spp. (9 examples), Orphulella pelidna (5), and an
undetermined species of Oedipodinae (2). The grasshoppers were placed in
the cells head inward and ventral or dorsal side upward or on the side. The
wasp weighed 23 mg and the prey averaged 14.3 mg (range = 9–27, n = 16).
Wasp eggs, ca. 2 mm long, adhered to the basal left (1) or right (2) forecoxal
intersegmental membrane of the innermost grasshoppers in the cells.
Field studies
Nest location. Tachysphex a. apicalis nested in bare soil or soil with
a minimum of vegetation, often the upper portions of sand cliffs along
watercourses. The cliffs formed 80–90° angles with the horizon. The soil
consisted of tan, gray, or white, dry to moist, compact layers of fine to coarse
stratified sand. Some females nested in soil where the slope was 45–60°. The
high density of individuals nesting in the vertical slopes may have forced
these wasps to occupy less vertical areas elsewhere. A few females attempted
to nest in loose, level sand, but their attempts were largely unsuccessful.
An aggregation of T. a. apicalis was found underneath a recently constructed
concrete bridge spanning the Peace River, 1 km west of Arcadia,
fl(TX-5). More than 50 wasps nested in a 1.2-m-high, hard-packed sand
cliff forming the western bank of the river during 3–19 July 1962. Wasps
also nested at that site 25–26 March 1963, 28 March 1965, 6 April 1966,
and 29 March 1968. The entire nesting area was devoid of direct sunlight,
contained no vegetation, and never received rainfall. In July 1962, nest
entrances dotted the upper third of the cliff for a distance of 15 m. I unearthed
95 nests overall and 19 nests at the center of the aggregation in an
area 55 cm long. Many entrances were 2–4 cm apart with only 1.7 cm separating
two openings. Nests on the periphery of the aggregation were 30–50
cm apart.
This species also nested in the upper portion of a 2.8-m-high, man-made
sand cliff at the Archbold Biological Station, Florida. Wasps were observed
there on 14 July 1962, 28 March 1965, and 1 April 1970. This site was not
given a site code number because nests were out of reach for excavation
and study.
Several females were studied and photographed at a 3-m-high sand cliff
forming one side of a drainage ditch near Lakeport, Glades County, fl(TX-
17; Fig. 38). This was a less dense aggregation than the one near Arcadia with
the closest entrances being 15–17 cm apart. Forty-one nests were excavated
in the upper third of the cliff 29 March–3 April 1963 and 29 March 1965.
Five females and their nests were observed and excavated in a sand cliff
forming one side of a Native American burial mound near Venus, Highlands
County, fl31 March–4 April 1963 (TX-18).
Activity conditions. Females in southern Florida nested from February to
December (R.C. Miller, 1973 pers. comm.). Nesting activity near Arcadia
was at its height on sunny days at air (shade) temperatures of 27–35 ºC. As
air temperature never fell below 27 ºC when making observations, it was
2009 F.E. Kurczewski 67
impossible to derive a minimum activity temperature. Nesting declined noticeably
or ceased entirely during periods of inclement weather, especially
rainfall, even though the aggregation near Arcadia was sheltered beneath the
concrete bridge. The rainfall must have impeded hunting and prey capture.
Females at that locality began nesting in numbers about 0900 (EST). The
earliest times for wasps bringing prey to nests were 0859, 0901, and 0908.
By 1800 (EST), most females in the aggregation had stopped nesting and
retired to open burrows, some with males already inside.
Burrow excavation. When beginning burrows, females walked slowly in
a zigzag manner across the sand cliff or steep slope. Wasps paused momentarily
every few centimeters and tapped their antennae slowly but incessantly
on the soil. Females resisted the pull of gravity by grasping the substrate
with their tarsal claws. Some wasps selected narrow ledges from which to
start digging. Such horizontal surfaces afforded them a positional advantage
over the smooth cliff face. Some females made up to eight attempts to excavate
a burrow before remaining in one place and finishing. Other wasps
stayed in one place and completed the burrow they started.
Females used their mandibles exclusively when starting an excavation,
producing an audible buzzing sound. One wasp, excavating with her mandibles,
clutched the soil around the opening with her tarsal claws for leverage.
Extensive use of the mandibles was required because of the compact stratified sand. Loosening the soil with the mandibles formed a cavity in the cliff
or slope. Females occasionally stopped, backed to the surface, and walked
in circles around the opening.
Figure 38. Western side of man-made drainage ditch near Lakeport, Glades County,
fl(TX-17). Tachysphex apicalis nested in the vertical sand cliff. Tachysphex similis
nested in level, loose sand of the field atop the cliff (TX-16).
68 Northeastern Naturalist Vol. 16, Monograph 3
A wasp used her forelegs in unison to throw the loosened sand backward
down the cliff or slope and out of reach. Her abdomen lifted up and down
in synchrony as the sand was flung backward. The mid- and hindlegs were
used only for walking and support. Females threw sand backward at the rate
of about 4–6 scuffs per second in direct sunlight (TX-17) and 2–3 times per
second in the shade (TX-5). Wasps attempting to dig in very loose sand in
the shade atop the sand cliff at Arcadia never completed a burrow because
the surface sand kept falling into the excavation and they couldn’t remove
it fast enough. One female spent over an hour making 16 excavations in the
loose sand, but none went to completion.
As an excavation progressed, a female rather slowly backed out to
remove the loose sand that accumulated in the burrow and entrance. This
removal was accomplished by flinging the sand backward beneath her abdomen
with her forelegs in unison. Her wings were held flat on her dorsum.
The intervals at which one wasp backed out to remove the loose sand usually
increased from beginning to end of an excavation—from an average of 15.3
sec for sand removal episodes 1–10 to 79.2 sec for sand removal episodes
57–66 (TX-5). The first few intervals generally consumed more time than
the next few intervals because it was necessary to penetrate the sand crust
by digging exclusively with the mandibles. Females spent up to 3.8 min for
the last interval inside the burrow, presumably to shape a cell.
Wasps nesting in sand cliffs never backed farther than 13–16 mm when
clearing soil from their burrows, and even that distance was attainable only
when a narrow ledge was present. Most females were limited to backing
out only 6–9 mm from the cliff face. Four wasps nesting in 10–20° sloped,
sunlit sand removed the soil backward to maximal distances of 13, 17, 20,
and 32 mm. One female’s maximal distance averaged 9 (6–12) mm during
sand removals 1–10 and 22 (17–30) mm for sand removals 56–65.
Females always backed out removing the loose sand in a rather straight
direction, being limited by the cliff face. They almost never turned sideways
or moved laterally. Very little sand accumulated around the entrance as most
fell down the cliff face or steep slope. Only one of four wasps nesting in
nearly level sand atop the cliff at Arcadia moved to the side when removing
loose sand from her burrow. The result of her excavation was a shallow
mound of soil about 30 mm wide and 50 mm long below and to the right of
the entrance. This female made no attempt to level or remove the tumulus.
Three wasps took 16, 43, and 72 min to complete a burrow and first
cell. The duration of excavation was correlated with burrow length; the
16-minute long dig produced a 49-mm long burrow and the 72-minute long
excavation resulted in a burrow 130 mm in length.
After making the cell, a female appeared in her entrance headfirst with her
wings held flat on her dorsum. Her antennae tapped the floor of the entrance,
and her abdomen pulsated rhythmically. Some wasps then turned around,
entered the burrow, flinging sand backward with their forelegs, turned around
2009 F.E. Kurczewski 69
inside the burrow, and re-exited headfirst 5–8 sec later (Fig. 39). Females then
made a series of circular orientation flights in front of the entrance, periodically
landing on the cliff face to rest and clean the antennae and mouthparts
with the forelegs before flying off in search of prey (Fig. 40).
Figure 39. Female Tachysphex apicalis exiting an open burrow to fly in search of prey
(TX-17). Note long digging spines on left foretarsus.
Figure 40. Female Tachysphex apicalis on a sloped sandy cliff ledge, pausing to clean
her mouthparts with her foretarsi (TX-5).
70 Northeastern Naturalist Vol. 16, Monograph 3
Additional cells. After provisioning the first cell and ovipositing on a
prey, the female may excavate a second and, later, third cell at the ends of
short side burrows off the main burrow. While making these burrows and
cells, the wasp appeared inside her entrance infrequently to remove loose
soil. She packed most of the sand from subsequent burrows into the burrows
of cells made earlier, below the surface and out of sight.
A wasp backed into an entrance flinging sand backward or she emerged
headfirst and raked sand backward into the burrow 20–25 min after beginning
a side burrow and second cell. Females digging a side burrow and third
cell backed from the excavation 11–13 min after taking in the last prey for the
second cell. Wasps backed out with loose sand only 4–7 and 3–6 times during
excavation of second and third cells, respectively. The intervals at which they
removed the loose sand were of longer duration than for the first burrow and
cell, averaging about 2 min. One female spent 32 and 27 min for excavation of
side burrows and second and third cells, respectively (TX-17). Wasps usually
did not make an extensive orientation flight after excavating a second or third
cell, having already familiarized themselves with their surroundings.
Females in Florida completed up to three fully provisioned cells per day
in April (TX-171) and July (TX-52).
Hunting. Females searched for prey on plants as far as 50–60 m from
their nests. They made slow, deliberate, winding and hovering flights, 10–15
cm high, facing the vegetation. One wasp (TX-17) hovered in flight near the
leaves and attacked a grasshopper from above. Two females stopped flying
and landed to pounce on a Chortophaga australior and Aptenopedes sphenarioides,
respectively, stinging the grasshoppers in their ventral thoraces.
One unidentified prey eluded a hunting wasp by jumping away. Hunting
females walked up plant stems, paused, and tapped their antennae on the
petiole, in some cases continuing up the stem to the next petiole, walking
onto the leaves and searching further (Fig. 41). The relative slowness with
which a wasp searched for prey may be connected with the capture of relatively
small nymphal grasshoppers that cannot leap far.
If unsuccessful in capturing prey, a female stopped hunting and returned
to her nest. She landed near the entrance, walked on the cliff face or slope
tapping her antennae, entered the burrow, and exited 6–8 sec later or took
flight without entering and returned to the hunting area. Several wasps
returned to their nests in flight, did not enter, but hovered in front of the
entrance for a second or two, turned in mid-air, and flew away. Periodic
returns to the nest were made at intervals of 4–23 min (n = 40).
Prey transport. After stinging a prey in the underside of its thorax near
a leg base, the female moved aside and cleaned herself. She then often
straddled the grasshopper ventral side upward and pressed her mandibles
against the soft intersegmental membrane surrounding the base of the prey’s
forecoxa. She grasped the bases of the prey’s antennae with her mandibles
and its body with her legs and took flight toward the nest (Fig. 42). Rarely,
grasshoppers were carried dorsal side upward instead of ventral side upward.
The relatively small prey was almost always carried directly to the nest in
2009 F.E. Kurczewski 71
a prolonged flight. However, a few wasps interrupted their flight to land on
vegetation and rest. All 199 examples of prey transport in this species involved
flight. The mean ratio of weight of prey to wasp was 0.8:1 (range =
0.23–2.70, n = 80).
Figure 41. Female Tachysphex apicalis searching for prey on sensitive plant (TX-5).
Her antennae continually tap leaflets and petiole.
Figure 42. Female Tachysphex apicalis flying toward entrance with prey (TX-17).
She grasps grasshopper’s antennae with her mandibles and its body with her legs.
72 Northeastern Naturalist Vol. 16, Monograph 3
Nest entry. The grasshopper was usually carried directly into the open
burrow, the wasp holding the prey tightly underneath (Fig. 43). As viewed
from behind, a provisioning wasp had her wings spread dorso-laterally as
she approached the cliff, but upon entering the burrow she rapidly brought
them downward and backward. After alighting inside the entrance, she continued
to run forward holding the grasshopper underneath and headfirst but
carried farther back. Prior to entering, some females with prey landed nearby
on the cliff or slope.
Wasps with larger prey released the grasshopper inside the opening
(Fig. 44), turned around, probably in the cell, walked up the burrow, grasped
the prey by an antenna and, with it, backed down the burrow. Females that
entered directly with prey reappeared headfirst in their entrances 6–33 sec
(mean = 16.8 ± 8.3, n = 38) after entering and flew away. Females spent 2–48
min (mean = 14.4 ± 10.7, n = 33) between consecutive entries with prey. One
wasp, whose entrance had been disturbed, flew in front of the cliff face for
over an hour before abandoning her grasshopper.
Final closure. A female began her final closure inside the nest in a headoutward
position. She pulled down soil from the top and sides of the main
burrow with her mandibles, sometimes producing a buzzing sound. The
loosened soil was thrown backward with her forelegs beneath her abdomen
as it synchronously moved up and down. This soil was tamped down at the
end of the main burrow by rapid repeated blows from the end of her abdomen.
The female first appeared in her entrance to get additional soil for the
fill 5–22 min (mean = 13.5 ± 12.0, n = 2) after entering with the last prey for
the cell.
Figure 43. Female Tachysphex apicalis flying directly into an open entrance holding
small grasshopper underneath (TX-17).
2009 F.E. Kurczewski 73
There was usually no loose soil available for use as fill, forcing the wasp
to scrape sand from the top and sides of the opening with her mandibles. She
removed sand from around the entrance, raked the loosened soil down the
burrow with her forelegs, and tamped it in place by repeated blows from
the end of her abdomen. The entrance enlarged considerably as she continued
to scrape sand from around it. The wasp stood on hindlegs and, hanging
onto the sides of the enlarged cavity with her midlegs, pulled down additional
sand with her mandibles and forelegs (Fig. 45). After several minutes
of such behavior, she walked around the opening a few times and flew off
leaving a 12–15 mm high, 14–19 mm wide, and 5–10 mm deep depression
in the cliff face or slope. Closures (TX-5) of burrows 49 and 130 mm long
took 19 and 42 min, respectively, from beginning to end.
Nest structure and dimensions. Burrows penetrated the sand cliffs in
nearly straight lines sloping slightly with the cliff faces (Fig. 46). Only
56 of 147 (38.1%) burrows exhibited lateral curvature of more than 22.5°
(Fig. 21). A few burrows coursed inward sinuously, following veins of soft
sand. Burrows were 5.0–6.5 mm and entrances were 6.0–8.0 mm in diameter.
The relatively large entrances were wide enough to allow simultaneous entry
of wasp and prey.
Several finished nests were three-celled (Figs. 21, 46). Females prematurely
closed some nests with only one or two cells at the onset of
rainfall, extreme cloud cover, or dusk. Most nests had second and third
cells at the ends of short side burrows leading from the main burrow.
Side burrows from the main burrow to a second cell left the main burrow
at distances of 29–41 mm (mean = 36.2 ± 4.6, n = 5) from an entrance.
Figure 44. Large prey of Tachysphex apicalis released just inside entrance (TX-17).
Wasp turned around inside nest and pulled in grasshopper seconds later.
74 Northeastern Naturalist Vol. 16, Monograph 3
Side burrows from the main burrow to a third cell left the main burrow
at distances of 17–25 mm (mean = 20.3 ± 4.2, n = 3) from an entrance.
Some females in attempting to excavate an additional burrow and cell
encountered clay, stones, roots, pieces of wood, and other debris. Wasps
Figure 46. Enlarged entrance, main burrow, and first cell of Tachysphex apicalis nest
exposed in excavation of cliff face (TX-17). Paralyzed grasshoppers are positioned
head inward and mainly ventral side upward in cell. Sand-filled second and third
burrows furcate from main burrow toward entrance.
Figure 45. Female Tachysphex apicalis standing upright inside entrance area to pull
down sand with her mandibles for final closure (TX-17).
2009 F.E. Kurczewski 75
Table 11. Burrow length (mm)1 in Tachysphex a. apicalis nests.
Site (TX- , year) n Range Mean ± SD
Arcadia, fl(TX-5, 1962) 95 32–95 62.9 ± 13.62
Arcadia, fl(TX-5, 1963) 4 49–62 56.0 ± 5.72
Arcadia, fl(TX-5, 1965) 1 130 130.0
Lakeport, fl(TX-17, 1963) 39 45–79 63.0 ± 8.22
Lakeport, fl(TX-17, 1965) 2 107–122 114.5 ± 10.61
Venus, fl(TX-18, 1963) 5 46–66 54.8 ± 7.40
1Includes cell length.
Table 12. Species of prey of Tachysphex a. apicalis, listed in alphabetical order.
Species of prey (nymphs) No. specimens
Achurum carinatum (Walker) 26
Amblytropidia mysteca (Saussure) 10
Aptenopedes sphenarioides Scudder 5
Arphia granulata Saussure 22
Chortophaga australior Rehn and Hebard 16
Dichromorpha viridis (Scudder) 1
Melanoplus keeleri (Thomas) 1
Melanoplus puer group 13
Melanoplus sanguinipes vulturnus Gurney and Brooks 9
Melanoplus seminole Hubbell 179
Melanoplus seminole Hubbell (adult male) 2
Orphulella pelidna (Burmeister) 71
Psinidia fenestralis (Serville) 3
Spharagemon marmorata picta (Scudder) 11
Trimerotropis maritima (Harris) 74
abandoned such excavations and dug elsewhere, leaving short incomplete
burrows or spurs. Females, sometimes in tandem with one or more males,
spent the night and periods of inclement weather in a head-outward position
in such a spur.
Second and third burrows and associated cells were dug with equal
frequency off the left (27) or right (28) side of a main burrow. However,
females always excavated a second and third burrow and adjoining cells off
one side or the other of the main burrow. The distance from first to second
cell was 17–60 mm (mean = 34.9 ± 11.0, n = 18) and from second to third
cell, 5–30 mm (mean = 22.1 ± 10.3, n = 5).
The cells were oval-elongate in shape, 6–11 mm (mean = 8.2 ± 1.1, n =
45) high, 6–11 mm (mean = 8.3 ± 1.1, n = 44) wide, and 12–22 mm (mean
= 15.5 ± 2.7, n = 45) long. Burrow length was variable at three localities,
probably due to site limitations (Table 11). Cell depth was variable because
of the diverse nesting sites. Cell depth from the top of the cliff or slope to
the bottom of the cell ranged from 2 (TX-5) to 55 cm (TX-17).
Prey. Females preyed almost entirely on rather small nymphal Acrididae
belonging to the subfamilies Gomphocerinae (108 specimens, 24.4%), Oedipodinae
(126, 28.4%), and Melanoplinae (209, 47.2%) (Table 12). Two adult
male Melanoplus seminole Hubbell were included among the 443 prey that
76 Northeastern Naturalist Vol. 16, Monograph 3
were identified. The wasps captured 11 genera and 14 species of prey Acrididae
(Table 12). All three subfamilies and as many as four genera and species
of Acrididae were found in a single cell (TX-5). Most of the prey were common
species, and the wasps appeared to be capturing whatever was available
in the nesting area (A.B. Gurney, US National Museum, Washington, DC,
1963 pers. comm.). It was impossible to discern generational differences
in prey species as both the wasps and grasshoppers were active throughout
much of the year.
The number of grasshoppers stocked in fully provisioned cells was 2–12
(mean = 7.1 ± 2.6, n = 40). The number of prey per cell at one locality (TX-5)
decreased from an average of 8.6 (range = 4–11) in cell 1 to 6.7 (range = 4–10)
in cell 2 to 5.5 (range = 2–9) in cell 3 (n = 23 cells). Individual prey ranged
from 4.0 mm (Amblytropidia mysteca, Melanoplus seminole) to 19.0 mm
(Achurum carinatum) in body length and weighed 4–50 mg (mean = 16.2 ±
22.3, n = 148). The wasps weighed 17.0–30.5 mg (mean = 23.8 ± 5.7, n = 5).
Aggregate prey weight per cell was 46–197 mg (mean = 114.3 ± 50.3, n = 21).
Of 459 prey placed in the cells, 410 (89.3%) were positioned head inward
and ventral side upward or on their side (Fig. 46), 42 (9.2%) head inward and
dorsal side upward, 6 (1.3%) head outward and ventral side upward, and 1
(0.2%) head outward and dorsal side upward.
Egg. The wasp’s egg was usually laid on a grasshopper at the bottom or
farthest back in the cell after the full complement of prey was placed inside.
One egg was laid on the uppermost grasshopper in the cell. Twenty-five of
28 (89.3%) eggs were placed on a grasshopper positioned head inward and
ventral side upward or on the side; 3 (10.7%) eggs were put on a prey that
was head inward and dorsal side upward. Eleven of 21 (52.4%) eggs were
laid on the heaviest grasshopper in the cell, 4 (19.0%) on the second heaviest,
3 (14.3%) on the lightest, and 3 (14.3%) on other grasshoppers. The eggbearing
individual weighed, on average, 30.0 ± 10.1 mg (range = 13–46, n =
21) or nearly twice as much as an average-sized prey (mean = 16.2 ± 22.3
mg, range = 4–50, n = 148) (P < 0.05).
The egg was slightly curved, sausage-shaped, white or cream-colored,
and affixed by the less tapered distal end to the soft intersegmental membrane
surrounding the base of a procoxa, lying transversely between the front and
midlegs of the prey. Live eggs were 1.7–2.2 mm (mean = 1.93 ± 0.13, n = 11)
and 0.4–0.6 mm (mean = 0.46 ± 0.05, n = 11) in length and width, respectively.
Ten of 28 (35.7%) eggs were attached to the intersegmental membrane surrounding
the base of the left forecoxa, and 18 (64.3%) to the intersegmental
membrane surrounding the base of the right forecoxa. In 4 two-celled nests,
both eggs were affixed to the same (left or right) side. However, in 2 threecelled
nests, eggs were attached to both the right and left sides.
Tachysphex apicalis fusus
Literature review
Most studies on the nesting behavior and prey of this geographic variant
of T. apicalis are reported under the name T. fusus. Williams (1914) noted a
2009 F.E. Kurczewski 77
female in the town of Pratt, Pratt County, KS “endeavoring to fly” with an
immature Melanoplus larger than herself. He noted another female in Ness
County, KS nesting in a “nearly vertical bank of earth.” The burrow was
“two and one-half inches” long, single-celled, and contained two immature
“Tryxalinae” (= Gomphocerinae?) in the cell. Williams (1932) recorded
Oxya chinensis (Thunberg) (Oxyinae) as prey of this species in Hawaii.
Rau and Rau (1918) noted a female of “T. fuscus” digging in loose mortar
of an abandoned building foundation in Missouri. The wasp attempted several
excavations in over an hour to no avail. A second female of this species
dug a horizontal burrow halfway down an ant-lion pit.
Elliott and Kurczewski (1985) reported a female of T. apicalis fusus at St.
Anthony, ID excavating in soft sand of a prior excavation. Upon completion
of the burrow, she left the entrance open, oriented in a hovering flight, and
flew away. Upon returning with prey, she landed near the opening or up to
1.5 m away before resuming flight to the nest. All grasshoppers were taken
directly into the open entrance without pausing. The female averaged 5.5
min between eight successive provisioning trips and spent 2 min inside between
entry and exit. The unfinished nest consisted of a burrow, 7.5 cm long,
with a single cell. The cell contained seven nymphal acridids. The female
was flying with an eighth prey when collected. The grasshoppers were all
identified as Melanoplus sanguinipes. They were positioned in the cell head
inward and ventral side upward or on the side.
Insect Museum Specimens
A female from near the Anacostia River, Prince George’s County, MD
(October 13, 1878; Collection T. Pergande) was collected with two immature
grasshoppers, Melanoplus femurrubrum and Chortophaga viridifasciata.
The label reads “in sand-bank. tunnel filled with young C. f. rubrum & Tr.
viridifasciata.” This notation was the first hint that this species nests in
strongly sloping sandy situations.
A female from Milt’s Pit, 4 mi. SW Davidsonville, Anne Arundel County,
MD (September 2, 2007; M. Buck) was collected “along a sandy path … at
the bottom of a slope, formerly a sandpit. The wings of the specimen show
almost no wear—only a tiny piece missing from the forewing” (M. Buck,
2008 pers. comm.). Another specimen from Windsor, Essex County, ON,
Canada (July 31, 2002; M. Buck) was captured “on a sand patch … amidst
a small circular track eroded out by dirt bikes” (Buck 2004; M. Buck, 2008
pers. comm.).
Field studies
Nest location. Two females of T. apicalis fusus (TX-52) were observed
nesting in a hard-packed, 2-m-high sand cliff along State Route 25 about 9
km south of Lakin, Kearny County, KS on 27–28 August 1964. One wasp
was followed through five unfinished excavations and two fully provisioned
one-celled nests. This small aggregation was probably in its late-season
stages as inferred from three single-celled nests with unidentifiable
78 Northeastern Naturalist Vol. 16, Monograph 3
grasshopper fragments and mature wasp larvae ready to make cocoons. The
five cells were located 85–156 cm from the top of the cliff.
Two other females (TX-71) nested in a steeply sloped, 1.5-m-high,
coarse sand–fine gravel bed of the Santa Fe Railroad, 6 km southeast of
Lecompton, Douglas County, KS on 12–17 September 1965. One wasp was
followed through six incomplete excavations and five successful singlecelled
nests over six days. Nests were located about 70–80 cm from the top
of the railroad bed.
Activity conditions. Observations were made from 0950 to 1630 (CDT)
at an average sand surface temperature of 44 ºC (TX-52) and from 1000 to
1630 (CDT) at air and sand surface temperatures of 25–29 °C and 45–49 ºC,
respectively (TX-71).
Burrow excavation. Females searched in shallow depressions or on
narrow ledges, 1–5 cm wide, pausing frequently and sampling with their
mandibles when looking for a place to begin an excavation. Wasps dug
considerably with their mandibles before using their forelegs in unison to
remove the loosened soil backward. An intermittent buzzing sound was
produced when using the mandibles. Upon abandoning an excavation, some
females turned away from the opening and threw sand into it using their forelegs
in unison. One wasp spent 41 sec breaking down the top of the entrance
with her mandibles before leaving. Wasps dug for 40 sec to 3.75 min before
abandoning an excavation. Abandoned excavations started from the surface
were only 2–5 mm deep, whereas one begun in a pre-existing hole was 28
mm long. Females abandoned from two to six excavations before remaining
in one place and finishing a burrow.
At intervals, a wasp backed from her excavation to remove the loosened
soil that accumulated in the burrow. This action was accomplished by flinging
the soil backward beneath her abdomen as it raised synchronously, using
her forelegs in unison. One wasp (TX-52) made a hovering flight in front
of the opening during 10 of her first 11 entries into the burrow to get sand.
The intervals at which another female backed from her burrow to remove the
loose sand usually gradually increased in duration as she dug deeper—from
an average of 21 sec for the first 2 min to an average of 69 sec for the last
2 min. Females removed loose sand from the burrows and entrances 31–45
times (mean = 38.0 ± 6.1, n = 5) during an excavation. At the beginning,
wasps stayed in the entrances only 3–5 sec before reentering the burrows, but
near the end of an excavation, they remained in the entrances an average of 7
sec. The distance to which they backed from the entrance with the loosened
soil averaged 13 mm throughout the excavation. This short distance was
related to the limitation of the cliff or slope. Excavation of the main burrow
and first cell took 18–43 min (mean = 30.4 ± 9.3, n = 6).
After excavating two burrows and adjoining cells, one female (TX-52)
appeared in her entrance headfirst each time moving her head from side to
side, turned around, and reentered the burrow flinging sand backward with
her forelegs. Before reentering, she hovered briefly in front of the entrance,
2009 F.E. Kurczewski 79
landed on the cliff face, and held her antennae straight out. Another wasp
(TX-71), after excavating five burrows and cells, exited each time tapping
her antennae on the entrance floor. She made a hovering flight about 15
cm in height, turning around once in mid-air in front of the entrance and
reentered the burrow. Once, she made three such flights followed by reentry
and re-exit. The different exit behavior of the two wasps may have been
related to the different habitats—a vertical sand cliff (TX-52) and a sloped
sandy-gravelly railroad embankment (TX-71). In both cases, exit behavior
culminated in 22–29-second-long, 15–20-cm-high hovering orientation
flights of increasingly larger radii followed by long, winding flights to the
nearest vegetation.
Females in Kansas (TX-522, 712) completed only one fully provisioned
cell per day in late August–September.
Hunting. One female (TX-52) was seen hunting on upright and decumbent
vegetation about 20 m from her nest. She flew from plant to plant and
walked up and down the stems and on the leaves tapping her antennae alternately.
This wasp returned to her nest without prey at intervals of 8, 11,
14, and 46 min, landed near the entrance, and flew off or hovered in front of
the opening for a second or two before flying away. Another female (TX-71)
was seen hunting similarly. She caught a green Chortophaga viridifasciata
on low-growing vegetation, stung it once in its ventral thorax near a leg base
for 4 sec, and then again near a different leg base for 7 sec before grasping
it and flying off.
Prey transport. One female (TX-71) transported 17 grasshoppers consecutively
in flight, regardless of their size. The wasp weighed 19 mg and her
prey ranged in weight from 8 to 45 mg. The ratio of weight of the heaviest
grasshopper to that of the female was 2.37:1. All grasshoppers were held
ventral side upward by their antennae with the wasp’s mandibles and by the
sides of their body with the wasp’s legs.
Nest entry. The wasp took 12–67 min (mean = 45.6 ± 19.6, n = 8) between
entering her nest with consecutive prey items over a three-day period (TX-
71). Her smallest grasshopper (weight = 24 mg) was taken directly into the
burrow. The other seven individuals (weights = 26–45 mg) were released
ventral side upward just inside the entrance with their abdomens protruding
1–4 mm beyond the opening. In each case, the female turned around, probably
in the cell, walked up the burrow, and pulled the grasshopper down the
burrow by an antenna 6 to 11 sec later. Twice, this wasp released a prey atop
the railroad embankment and applied her mandibles to the base of its foreleg
before resuming transport to the entrance.
Final closure. One female made two final closures on separate days at
1430 and 1535 at sand surface temperatures of 49 and 45 ºC (TX-71). She
appeared headfirst in the entrances 6 and 5.5 min, respectively, after taking
in the last prey for the cell. With her head directed toward the entrance, she
pulled down soil from the top and sides of the burrow with her mandibles
and flung this soil backward beneath her abdomen with her forelegs in
80 Northeastern Naturalist Vol. 16, Monograph 3
unison. Her appearances in an entrance decreased from 23–62 sec at first
to 7–10 sec later as she filled the burrow, except for one period where she
remained out of sight for over 6 min. During the first closure, she stayed
outside breaking down the entrance for only 3–6 sec, followed by a single
hovering flight before backing down the burrow. For the second closure,
she stayed outside breaking down the entrance for 4–13 sec before backing
down the burrow, except for a 42-sec-long period of such behavior before
disappearing inside for over 6 min. Following both closures, the wasp
turned toward the entrance three times. Durations for the two closures were
11.5 and 18.0 min.
Nest structure and dimensions. Females excavated short, single-celled
nests that entered the cliff face almost perpendicularly (TX-52) or descended
at an angle of 25° or less to the sloped embankment (TX-71). Burrows dug
into the cliff face were straight or, at most, slightly curved, while those in the
sloped embankment exhibited much curvature. Entrance diameter was 5–6
mm and burrow diameter, 4–5 mm regardless of soil type.
Burrows in the hard-packed sand cliff were longer (mean = 62.6 ± 7.5
mm, range = 54–72, n = 5), including cell length, than burrows in the more
loose soil of the sloped embankment (mean = 48.4 ± 7.1 mm, range = 41–60,
n = 5). Cell size (length x height x width) averaged about the same at the two
locations: 13.7 x 7.0 x 7.7 mm (TX-52: range = 13–14 x 7 x 7–8, n = 3), and
14.3 x 7.0 x 7.8 mm (TX-71: range = 12–18 x 6–8 x 7–8, n = 4). The cells
were oval to oval-elongate in shape.
Prey. Females preyed on nymphal Oedipodinae and Melanoplinae
(Acrididae) as follows: Arphia simplex Scudder (6 examples; TX-52, 71),
Melanoplus sp. (4; TX-52), and Chortophaga viridifasciata (15; TX-71).
Chortophaga viridifasiata included both gray-streaked and green color
forms (A.B. Gurney, 1969 pers. comm.).
The number of grasshoppers placed in the cells for larval food averaged
4.0 (range = 4, n = 2; TX-52) and 3.4 ±0.5 (range = 3–4, n = 5; TX-71).
Individual prey weighed, on average, 16 (n = 1; TX-52) and 31.4 ± 8.5 mg
(range = 8–45, n = 17; TX-71). Two wasps weighed 15 mg (TX-52) and 19
mg (TX-71). Four other grasshoppers (probably Melanoplus sp.) collected
from provisioning females measured 5.0–8.5 mm (mean = 6.6, n = 4; TX-52)
in body length. The mean aggregate weight of prey per cell was 106.8 ± 19.8
mg (range = 88–140, n = 5; TX-71).
Nineteen of 21 (90.5%) prey in the cells were positioned head inward
and ventral side upward or on their side. One grasshopper was placed head
inward and dorsal side upward (TX-71), and one was atypically positioned
head outward and ventral side upward (TX-52).
Egg. The wasp’s egg was as described for T. a. apicalis in shape, size, and
coloration. It was affixed by the less-tapered, distal end to the soft intersegmental
membrane surrounding the base of the prey’s forecoxa. The proximal
end extended free to the opposite side, the egg lying transversely between
the bases of the fore- and midcoxae. Four of five eggs (TX-71) were attached
2009 F.E. Kurczewski 81
to the base of the right forecoxal intersegmental membrane of the prey. The
grasshopper bearing the wasp’s egg was placed head inward and ventral side
upward in all five cells (TX-71). It averaged 33.4 ± 6.1 mg (range = 24–41,
n = 5; TX-71) in weight, or slightly heavier than the mean weight of other
prey in the cells (31.4 mg). The egg was laid on the heaviest (2 examples),
second heaviest (1), third heaviest (1), or lightest grasshopper (1) in the cell.
The egg-bearing prey was the first or second individual taken into the nest.
Discussion
The nesting behavior of seven species in the Tachysphex terminatus group
is documented in this study. Six of the species nest in level or slightly sloping
friable soil (Table 13). Tachysphex apicalis nests mainly in sand cliffs
and strongly sloped sandbanks (Kurczewski and Snyder 1968). Tachysphex
antillarum, T. terminatus, T. similis, and T. apicalis often form dense aggregations.
Females of these species, T. clarconis, and T. alpestris excavate
multi-celled nests, with the result that emerging adults are immediately in
close contact. The males resemble the females in size and coloration. Sexual
differences or recognition characters are not exaggerated as in the more solitary
species (Kurczewski 1966b). Similarity in appearance of the sexes may
be subtly connected with the gregarious nature of the nesting aggregation.
In dense monospecific aggregations, males and females probably spend less
time locating one another.
The external morphology and nesting behavior of T. apicalis reflect
its atypical habitat. Tachysphex apicalis has a shiny frons, slightly less
Table 13. Important ecological and behavioral characteristics of the Tachysphex terminatus
species group. Abbreviations: Levels sand surface = levels sand surface during burrow excavation;
Temp clos = temporary closure of nest entrance; + = present; 0 = absent; - = no record;
No prey/cell = number of prey per fully provisioned cell; No. cells/nest = number of cells per
completed nest.
Levels
sand Temp Transport Prey No prey/ No. cells/ Stage,
Species Habitat surface clos method size cell nest type prey
clarconis Level sand + + Flight Small 3–6 2–3 Nymphal
Acrididae
antillarum Level sand + + Flight Small 6–11 1–5 Nymphal
Acrididae
alpestris Level sand - + Flight Small 2–13 1–3 Nymphal
Acrididae
linsleyi Level sand - + Flight Small 7 1 Nymphal
Acrididae
terminatus Level sand, + + Flight Small 1–14 1–5 Nymphal
sandbank Acrididae,
Tettigoniidae
similis Level sand + + Flight Small 1–15 1–5 Nymphal
Acrididae
apicalis Sand cliff, 0 0 Flight Small 2–12 1–3 Adult,
sandbank nymphal
Acrididae
82 Northeastern Naturalist Vol. 16, Monograph 3
setaceous integument, stout mandibles, narrow clypeus with medial
projection, and more rectangular frons than other species in the group—
all possible adaptations related to cliff nesting and absence of temporary
closure. As many as three males in single file and two males and a female
of T. apicalis in tandem may occupy the same open burrow at night and
during inclement weather, a rarity in this genus. Males of this species lack
long foretarsal digging spines and do not excavate their own burrows.
Males of T. terminatus and T. similis have well-developed tarsal rakes on
their forelegs with which they dig short resting and overnight burrows in
the soil (Kurczewski 1966b).
In initiating a burrow, T. apicalis uses its mandibles considerably in order
to penetrate the hard-packed sandy cliff face. The stout mandibles and
medial clypeal lip projection of this species may be adaptations to facilitate
such behavior. With respect to the velocity of digging, T. apicalis uses the
forelegs more slowly than T. terminatus, and T. terminatus uses them more
slowly than T. similis. This difference may reflect the different sizes of the
species, T. apicalis being the largest, T. similis the smallest, and T. terminatus
intermediate in size. There are no noticeable differences between T.
terminatus and T. similis in the number of entries to remove sand from the
burrow and duration of burrow excavation. The practice of partly filling the
entrance of an abortive burrow before abandoning the excavation is well
developed in T. terminatus and T. similis, species that make a temporary
closure of the nest entrance.
Species that inhabit level sand such as T. clarconis, T. antillarum, T.
alpestris, T. linsleyi, T. terminatus, and T. similis temporarily close the
entrance with loose sand upon leaving the nest. All species except T. alpestris
and T. linsleyi have been reported to elaborately level the sand surface
near the entrance prior to making the temporary closure (T. alpestris and T.
linsleyi probably have not been observed enough to establish this behavior as
part of their repertoire). The complexity and duration of the leveling process
increase as burrow excavation proceeds toward completion. Tachysphex apicalis
is limited by its habitat since most sand from burrow excavation falls
down the cliff face or steep sandbank and out of reach. This species leaves
the nest entrance open when it goes in search of prey.
Tachysphex terminatus spends about twice as much time as T. similis for
removal of the temporary closure and temporary closure of the entrance at
the same sand surface temperatures regardless of geographic location (P <
0.0001). The more rapid entry and exit of T. similis may be related to its
smaller size, faster movements, and looser temporary closure. Both species
display these behaviors increasingly more rapidly in a straight-line relationship
as sand surface temperature rises from 35 to 60 ºC. During removal of
the closure and closure, T. terminatus makes hovering flights into cooler
strata of air to avoid the hot sand when surface temperature reaches 55 ºC.
Such flights increase in number as the sand surface temperature reaches 59–
61 ºC and then decrease in number, concurrently giving way to an aborted
2009 F.E. Kurczewski 83
temporary closure. Tachysphex similis does not typically exhibit hovering
flights at high surface temperatures, but instead, makes an increasingly
looser temporary closure and leaves the entrance progressively more open
above 57 ºC. The end result for both species at sand surface temperatures
exceeding 60°C is a partly open entrance to allow for rapid entry with prey
and avoidance of the hot sand.
Species in the terminatus group capture mostly early nymphal stages of
grasshoppers that frequent the leaves and stems of vegetation. The wasps fly to
a nearby source of vegetation to hunt for prey after making a characteristic orientation
flight. They are able to hunt for prey at distances as far as 30–60 m from
their entrances because they rapidly transport relatively small grasshoppers
to the nests in flight. Relatively small prey and rapid flight transport allow the
various species to capture and stock several to many individuals per cell within
a rather brief period and complete up to 3 to 5 fully provisioned cells per day.
Species in the terminatus group often transport prey directly to the nest
in a prolonged flight. The species possess longer wings with greater total
surface area than some other species of Tachysphex that practice ground
transport of larger grasshoppers. An increase in the size of the hindwing
(jugal lobe) in some species groups of Tachysphex apparently increases
their flight velocity, enabling them to fly more rapidly than other groups
with smaller hindwings (Pulawski 2007). The relatively larger, more robust
thorax of species in the terminatus group may house a more extensive flight
musculature to facilitate flight transport. The relatively shorter legs of these
species probably represent an adaptation for holding smaller prey. Evans
(1962) believed that “shorter legs may be better adapted for holding the prey
tightly beneath the body in flight.”
Species in the terminatus group that nest in level soil and make a temporary
closure release the grasshopper ventral side upward or on its side with
the head near the sand-filled entrance. Such a placement facilitates the wasp
pulling the prey into the nest by an antenna. The grasshopper is nearly always
positioned in front of the entrance in a straight line or at a slight angle
with the direction of the burrow. Tachysphex apicalis, on the other hand, is
confined to carrying its prey directly into the open entrance because of the
limitations of the sand cliff or steep sandbank. Smaller prey are carried directly
down the burrow, while larger individuals are released just inside the
entrance and pulled in from inside after the wasp turns around.
Species that nest in level soil rake the sand backward with the tarsal
comb of the forelegs when filling the burrow and closing the fully provisioned
nest. The apical segments of the foretarsi are bent medially to expose
more spines for catching the sand grains and flinging them backward. The
soil flung backward is then tamped in place at the end of the burrow with
the shiny, trowel-shaped pygidium and sub-terminal abdominal segments.
Tachysphex similis females make fewer trips onto the sand surface to retrieve
soil for the fill despite the burrows of this species and T. terminatus being
equivalent in length at common localities.
84 Northeastern Naturalist Vol. 16, Monograph 3
When nesting in cliffs and steep slopes, T. apicalis, T. terminatus, and,
rarely, T. similis close the nest by pulling down sand from around the entrance
with the mandibles, as they are limited from obtaining loose sand
by the vertical or strongly sloping sites. During the final stages of this type
of closure, females stand upright on hindlegs inside the enlarged entrance,
grasp the sides of the cavity with their midlegs, and loosen sand with their
mandibles. Such completed nests are never filled flush, but remain readily
visible as a concave depression on the rather smooth surface.
The nests of species in the terminatus group enter the level sand obliquely
and are relatively short and shallow. The nests of T. apicalis are slightly
sloped in sand cliffs and steep sandbanks and are also relatively short and
shallow. Under optimal conditions, the completed nests of all species in
the group are two- to five-celled. Multi-celled nests are usually associated
with dense aggregations and nesting in close proximity. Conserving space
by making a single multi-celled nest rather than several uni-celled nests is
advantageous where the amount of suitable soil is limited.
A decrease in T. terminatus and T. similis mean burrow length and mean
cell depth from spring to late summer at many locations is inexplicable.
The two or more generations of wasps often nest in approximately the same
soils, thus eliminating a difference in soil type or texture as an explanation.
Longer and deeper nests in the first generations of the two species
coincide with higher soil moisture content. However, the reverse is true in
other fossorial wasp genera where deeper nests are excavated in drier soil
(Alcock and Ryan 1973, Hager and Kurczewski 1986, Kurczewski 2002,
Kurczewski and Wochadlo 1998). Generational differences in mean burrow
length and mean cell depth in T. terminatus and T. similis may be connected
with seasonal day length and resulting sand temperatures or, in the Northeast,
the amount of snow cover.
In New York, females of T. terminatus are slightly larger in the second
generation, having been reared from more prey biomass in the first generation
cells (Elliott and Kurczewski 1975; F.E. Kurczewski, pers. observ.).
However, there is no correlation between wasp size (weight) and cell depth
in T. terminatus. In T. similis, on the other hand, larger Florida females
consistently dig deeper nests than smaller Kansas females. There is no
difference in mean cell depth between the equivalent-sized all-black and
red-tipped females of T. similis in Kansas.
Species in the terminatus group stock their cells with small, mainly
nymphal grasshoppers (Acrididae). A few females of T. terminatus stocked
several cells with a single small nymphal bush katydid (Tettigoniidae) in
addition to small nymphal grasshoppers during spring at a single locality
(Kurczewski 1966a). Tachysphex apicalis, the largest species in the group,
rarely stores adult male grasshoppers of smaller acridid species. Very large
sample sizes for T. terminatus and T. similis reveal equivalent percentages
of Gomphocerinae, Oedipodinae, and Cyrtacanthacridinae + Melanoplinae
as prey. Tachysphex apicalis stocks its cells with these same subfamilies of
2009 F.E. Kurczewski 85
prey, but in different proportion. All three subfamilies of Acrididae and up to
three or four genera and species of prey may be put in a single cell of these
three wasp species. Females are evidently unselective of the species of prey
and capture whatever nymphal grasshoppers of favorable size are available
and abundant near the nesting site (A.B. Gurney, 1963 pers. comm.).
Tachysphex terminatus and T. similis, except in Florida, stock different
species of prey in spring and mid- to late summer nests. There is a gradual
decrease in the number of prey species through the nesting season. Grasshoppers
from first-generation (May–June) nests include species of suitable
size that are available only at that time of year. By mid-summer, most of
these species are in the adult stage, too large for use, and the wasps switch
to other, albeit fewer, suitable-sized species of prey. Most second-generation
(mid-July–August) nests contain prey that were in the egg stage and unavailable
for use earlier in the year. Prey selection is thus connected with the
seasonal availability of acridid nymphs of appropriate stage and size. It is
difficult to discern prey differences for the different generations of T. similis
and T. apicalis in Florida because both wasps and prey grasshoppers are
available almost continually throughout much of the year.
Species in the terminatus group usually stock several or many small
prey in a fully provisioned cell. Cells with only one or a few prey are often
closed prematurely with the onset of inclement weather or dusk. One or two
prey per fully provisioned cell is also associated with scarcity of prey due to
drought or other unpredictable environmental events. There is a trend in T.
similis and T. terminatus to stock more, smaller grasshoppers per cell early in
the nesting season and fewer, larger grasshoppers per cell later in the nesting
season. The number of prey per cell is approximately halved from first to
later generations in T. terminatus. Not only are fewer grasshoppers stocked
in the cells later in the year, but there is also a reduction in the total biomass
of prey per cell, resulting in slightly smaller first-generation wasps the following
year.
Most of the grasshoppers captured by species in the terminatus group are
put in the cells head inward and ventral side upward. Cells with the largest
number of prey usually have more grasshoppers placed in other positions.
In such cases, the wasp, in maneuvering to oviposit after bringing in her
last prey for the cell, probably accidentally moves some of the grasshoppers
from their original head inward and ventral side upward positions to the
atypical positions in which some of the prey are found.
The egg is usually laid on a grasshopper at the bottom or one placed
farthest back in the cell, but only after the full complement of prey has been
put in the cell. An egg is not affixed to a grasshopper at the front end as this
prey might be readily discovered and attacked by enemies entering the cell.
The prey to which the wasp’s egg adheres is nearly always placed head inward
and ventral side upward or tilted slightly on its side. This grasshopper
is often one of the largest and heaviest prey in the cell as it is advantageous
for the young larva to begin feeding on a sufficient amount of food. In some
86 Northeastern Naturalist Vol. 16, Monograph 3
multi-cellular nests, a female places her eggs on one side or the other of the
grasshoppers in most or all cells. Other wasps may alternate between left and
right-sided affixation sites.
Acknowledgments
James Carpenter, Keith Goldfarb, Michael Ohl, and Wojciech Pulawski reviewed
the manuscript. Wojciech Pulawski kindly agreed to serve as Guest Editor. Richard
Archbold, Leonard Brass, Thomas Eisner, Bill Huff, John Lerg, Rob Line, Charles
Michener, Verne Pechuman, and Mary Rabe aided with equipment, funding, or facilities.
Noel Snyder, Edmund Kurczewski, George Matuza, Ann Peck, Nancy Burdick,
and Margery Spofford assisted with field studies. Noel Snyder added numerous
research tips and took the many photographs. Howard Evans initially proposed a comparative
nesting behavior study of Tachysphex terminatus and T. tarsatus (Say) for
my M.S. thesis and permitted me to use his field notes. Matthias Buck sent me his prey
records and observations on members of this group. Richard Bohart, Karl Krombein,
and Wojciech Pulawski confirmed my identifications of the wasp species. Ashley Gurney
and Dave Nickle determined the prey Acrididae and Tettigoniidae. Dan Dindal
and Charles Schirmer analyzed the soil samples. Diane Kiernan interpreted and analyzed
innumerable statistical data. She introduced alternative ways to present some
of the quantitative information. Don Artz formatted Figures 1, 16, and 17. Joe Stoll
retouched and image-scanned the photographs. Funds for this study were provided
by Sigma Xi-RESA Grants-in-Aid of Research, Cornell University Faculty Research
Fund, National Science Foundation Postdoctoral Fellowship and Undergraduate Research
Participation Programs, National Institutes of Health Postdoctoral Fellowship,
State University of New York-RESA Grants-in-Aid of Research, Michigan Chaper of
The Nature Conservancy, and New York State United University Professions.
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