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Antagonistic Behavior Between Evening Bats and Carpenter Ants
Michael J. Bender1,*, Steven B. Castleberry1, Darren A. Miller2,
and T. Bentley Wigley3
Abstract - We report on mist-net captures of three individual Nycticeius humeralis (Evening
Bat) with anterior portions of Camponotus fl oridanus (Florida Carpenter Ant) attached by the
mandibles. Based on head morphology, the ants were most likely alate queens captured as prey
during the ants’ nocturnal mating fl ights. No similar interaction between evening bats and ants
has previously been documented.
Evidence of antagonism between bats and ants in the United States has rarely
been reported. In the five cases we found reported in the literature, bats were collected
with the head of a Camponotus sp. Mayr (carpenter ants) attached to their
facial region. Handley (1956) concluded that such interactions occurred in fl ight
when bats pursued ants as prey. Although the genus of ant is consistent, four bat
species were involved in reported interactions. Two cases were noted for Eptesicus
fuscus Beauvois (Big Brown Bat; Handley 1956, Wilson 1958), and one each for
Tadarida brasiliensis I. Geoffroy (Brazilian Free-Tailed Bat; Ross 1961), Macrotus
waterhousii Gray (Waterhouse’s Leaf-Nosed Bat; Ross 1961), and Pipistrellus hesperus
H. Allen (Western Pipistrelle; Harris 1971). No interaction between Nycticeius
humeralis Rafinesque (Evening Bat) and ants has been reported. In May 2007, in
Decatur County, GA, we captured three Evening Bats with remains of ants attached.
Herein we report on capture and observation of these individuals.
Observation and Discussion. On May 29, 2007, while mist-netting over a small
pond within a managed pine (Pinus spp.) forest landscape, we captured a pregnant
Evening Bat with the anterior portions of two ants attached (Fig. 1). The ants were
firmly attached by their mandibles to the right side of the bat’s head, with one attached
at the base of the ear and the other near the eye. Both ants were missing the
abdomen and the posterior part of the thorax. The posterior portions of the ants were
presumably bitten off by the bat. Locations of attachment likely affected vision, hearing,
and foraging efficiency. It is unlikely that the bat was able to groom the ants off
because of the location and secure attachment. Upon release, the bat’s behavior did
not suggest lasting effects from the attached and subsequently removed ants.
On May 30, 2007, we captured two lactating Evening Bats with mist nets at a
different pond within the same managed forest, approximately 4.5 km away from the
previous pond, each with anterior portions of a single ant attached. We photographed
one bat with an ant attached to the left cheek (Fig. 2). Location of ant attachment
and photographs were not recorded for the second bat, but both ants were securely
attached by their mandibles with the bodies removed just below the head. Both bats
behaved normally upon removal of the ants and release.
Ants were preserved and later tentatively identified as alate queen Camponotus
fl oridanus Buckley (Florida Carpenter Ant). Identification was based on head
morphology by John Pickering (University of Georgia) and Stefan Cover (Harvard
University). The absence of complete specimens precluded us from identifying ants
with absolute confidence or determining conclusively if the ants possessed wings at
the time of interaction.
Seasonal timing of bat captures and location of ant attachment support assumptions
of aerial contact made previously by Handley (1956). Camponotus species,
including Florida Carpenter Ants, are primarily nocturnal (Sharma et al. 2004, Suiter
Notes of the Southeastern Nat u ral ist, Issue 8/1, 2009
180 Southeastern Naturalist Notes Vol. 8, No. 1
Figure 1. Adult female Nycticeius humeralis (Evening Bat) with anterior portions of two Camponotus
fl oridanus (Florida Carpenter Ants) attached by the mandibles.
Figure 2. Adult female Nycticeius humeralis (Evening Bat) with anterior portion of Camponotus
fl oridanus (Florida Carpenter Ant) attached by the mandibles.
2009 Southeastern Naturalist Notes 181
2003) and exhibit aerial swarming and mating behavior in spring. However, it is also
plausible, although unlikely, that this interaction occurred due to cohabitation of a
Bats are capable of discriminating between food items based on palatability
(Hristov and Conner 2005), size, and taxa (Agosta et al. 2003). Evening Bats rarely
include hymenopterans as a major prey item (Whitaker 2002, Whitaker and Clem
1992), but ants may be consumed extensively by many bats, including Evening Bats,
during periods of high abundance (i.e., swarming events; Carter et al. 2004). The
aggressive nature and occasional injuries associated with consuming carpenter ants
may not outweigh the benefits of a concentrated and abundant food source during
Acknowledgments. Funding was provided by Warnell School of Forestry and
Natural Resources at the University of Georgia, the National Council for Air and
Stream Improvement, Inc., and Weyerhaeuser Company. Research was conducted on
property owned by International Paper Company, which also provided field housing
and logistical assistance. We thank J. Pickering and S. Cover for assistance with ant
identifications and A. Forsberg for field assistance.
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by syntopic Eastern Red (Lasiurus borealis), Seminole (L. seminolus) and Evening
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Suiter, D.R. 2003. Biology and management of carpenter ants. University of Georgia Cooperative
Extension Service (CAES) Bulletin 1225:1–8.
Whitaker, Jr., J.O. 2002. Prey selection in a temperate-zone insectivorous bat community. Journal
of Mammalogy 85:460–469.
Whitaker, Jr., J.O., and P. Clem. 1992. Food of the Evening Bat, Nycticeius humeralis, from
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1 Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens,
GA 30602. 2Weyerhaeuser Company, PO Box 2288, Columbus, MS 39701. 3National Council
for Air and Stream Improvement Inc., PO Box 340317, Clemson, SC 29634. *Corresponding
author - email@example.com.