Predation on the Toxic Red-Spotted Newt (Notophthalmus
viridescens viridescens) by Lepomis macrochirus (Bluegill) and
L. auritus (Redbreast Sunfish) within an Urban Watershed
William I. Lutterschmidt, Riccardo A. Fiorillo, and Sidney M. Anderson
Southeastern Naturalist, Volume 14, Issue 4 (2015): N61–N63
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N61
2015 Southeastern Naturalist Notes Vol. 14, No. 4
W.I. Lutterschmidt, R.A. Fiorillo, and S.M. Anderson
Predation on the Toxic Red-Spotted Newt (Notophthalmus
viridescens viridescens) by Lepomis macrochirus (Bluegill) and
L. auritus (Redbreast Sunfish) within an Urban Watershed
William I. Lutterschmidt1,2,*, Riccardo A. Fiorillo3, and Sidney M. Anderson4
Abstract - Predation on Notophthalmus viridescens viridescens (Red-spotted Newt) is rare due to their
toxic skin excretions, which provide chemical defense against potential predators. Here we document
the occurrence of the Red-spotted Newt in the stomach contents of Lepomis macrochirus (Bluegill)
and L. auritus (Redbreast Sunfish), common sunfishes within an urban watershed in Columbus, GA.
The chemically mediated toxicity and unpalatability of Notophthalmus viridescens viridescens
(Rafinesque) (Red-spotted Newt) has been well documented (e.g., Brandon et al.
1979, Brodie 1968, Brossman et al. 2014, Hurlbert 1970, Marion and Hay 2011, Webster
1960). Thus, predation on the Red-spotted Newt is rare, and Rohr and Madison (2002) stated
that no significant predation on adults has been documented in the wild. If Red-spotted
Newts are preyed upon in number (e.g., 27 reported in Shure et al. 1989), only the viscera
are consumed and the toxic skin is discarded (Petranka 1998). Here, we cite a few reported
predation accounts from the literature and report on the occurrence of the Red-spotted Newt
in the stomach contents of 2 common sunfishes within an urban watershed within and surrounding
Columbus, GA.
As part of a study investigating helminth parasite-communities (Anderson et al., in
press), we dissected 222 Lepomis macrochirus (Rafinesque) (Bluegill) and 205 L. auritus
(L.) (Redbreast Sunfish) from 8 creeks within the Bull and Upatoi Creeks Watershed, Muskogee
County, GA. We used a backpack electro-fisher (Smith-Root® Inc., Vancouver, WA)
to collect fishes, and transported them live to our field laboratory. We noted no abnormal
behavior prior to euthanizing and dissecting the fish. We measured the body mass (g) and
standard length (mm) of each fish prior to dissection. We examined the eyes, eye cavities,
viscera (heart, spleen, liver, kidney, and gonads), and intestinal tract (intestinal mesentery,
intestinal lumen, pyloric ceca, and stomach) to detect helminth parasites.
Upon examining the stomach and intestinal tract of each sunfish, we found Sphaeriidae
(finger-nail clams), insect larvae, algae, partially digested fishes (Anderson et al.,
in press), and a partially digested salamander in each of 3 sunfishes. We were able to
identify 2 of the 3 salamander specimens to subspecies as Red-spotted Newt by using the
distinctive orange pigmentation, the 2 distinct rows of reddish-brown dorsal–lateral spots
encircled by darker pigment, and the reported subspecies distributions (Petranka 1998).
Each newt’s partially digested tail did not allow us to examine for the presence or absence
of a laterally compressed tail, which would have helped confirm whether the newts
were adults or terrestrial efts (i.e., adults have laterally compressed tails). However, each
newt lacked gills, and their snout–vent lengths (SVL) were smaller than those reported
for aquatic adults (31–54 mm, Petranka 1998; 29–51 mm in Georgia, Jensen et al. 2008)
1Department of Biological Sciences, Sam Houston State University, Huntsville, TX 77341. 2Texas
Research Institute for Environmental Sciences, Sam Houston State University, Huntsville, TX 77341.
3School of Science and Technology, Georgia Gwinnett College, Lawrenceville, GA 30043. 4Texas
Veterinary Medical Diagnostic Laboratory, Texas A&M University, College Station, TX 77843. *Corresponding
author - lutterschmidt@shsu.edu.
Manuscript Editor: David Steen
Notes of the Southeastern Naturalist, Issue 14/4, 2015
2015 Southeastern Naturalist Notes Vol. 14, No. 4
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W.I. Lutterschmidt, R.A. Fiorillo, and S.M. Anderson
suggesting that they were terrestrial efts. We fixed in a 10% formalin solution, preserved
in 70% ethanol, and deposited in the Sam Houston State Vertebrate Museum, Huntsville,
TX (SHSVM# 0008-2015, collector # WIL-02-2002) and (SHSVM# 0009-2015, collector#
WIL-03-2002) these 2 salamander specimens.
We removed the first newt specimen (SHSVM# 0008-2015, SVL = 28.7 mm) from a
Bluegill (126.5 mm standard length (SL), 30.94 g, data #: Lm-dz-04-w02) collected from
Dozier Creek on 21 February 2002. We removed the second newt specimen (SHSVM#
0009-2015; SVL = 22.8 mm) from a Redbreast Sunfish (108.7 mm SL, 42.08 g, data #:
La-rc-01-w02) collected from Randall Creek on 21 February 2002. We removed the third
unidentifiable salamander from a Redbreast Sunfish (112.0 cm SL, 21.39 g, data #: La-bc-
13-s02) collected from Bull Creek on 8 August 2002; this third salamander specimen was
not deposited due to our inability to identify the specimen to at least genus. Respective
creek-capture localities of each fish were the intersection of each creek with Macon Road
(US Highway 22). Georeferenced maps of creek localities are presented in the literature
(Anderson et al., in press; Martin and Lutterschmidt 2013).
Some documented accounts of predation on Red-spotted Newts include amphibians
(e.g., Lithobates catesbeianus (Shaw) [Bullfrog; Marion and Hay 2011] and Siren intermedia
Barnes [Lesser Sirens; Fauth and Resetarits 1991]), reptiles (e.g., Chrysemys picta
(Schneider) [Painted Turtle; Hurlbert 1970] Chelydra serpentina (L.) [Snapping Turtle;
Hurlbert 1970], Thamnophis sirtalis (L.) [Garter Snake; McGlothlin et al. 2014], and Heterodon
platirhinos Latreille in Sonnini and Latreille [Eastern Hog-nosed Snake; Feldman
et al. 2015],), and fish (e.g., Semotilus atromaculatus (Mitchill) [Creek Chub; Caetano and
LeClair 1996]). However, fish such as Salvelinus fontinalis (Mitchill) (Brook Trout) are
highly susceptible to the skin toxins of newts (Webster 1960) and almost never ingest them
(e.g., “Cursory observations on the stomach contents of several hundred trout from these
waters over the past ten years have failed to disclose the ingestion of a single newt, although
ecologically this salamander is readily available to the fish.” [Webster 1960]). Centrarchids
(e.g., Micropteris [bass] and sunfish) also seem to avoid these newts as prey due to their
unpalatability (Hurlbert 1970, Marion and Hay 2011). Our observation supports the seemingly
rare predation on the Red-spotted Newt (i.e., 2 newts observed within 427 sunfishes
sampled) but provides documentation of the occurrence of this newt as a potential prey item
for both Bluegill and Redbreast Sunfish.
Acknowledgments. We acknowledge a research grant awarded to W.I. Lutterschmidt
by the Engineer Research and Development Center (ERDC) and the Civil Engineering
Research Laboratory (CERL) of the US Army Corps of Engineers (ERDC-CERL Contract
#DACA 42-00-C-0047). All fish were collected under a permit (29-WMB-01-147) issued
to W.I. Lutterschmidt by the Georgia Department of Natural Recourses. We thank Hugh
Westbury of the Strategic Environmental Research and Development Program (SERDP),
Ecosystem Management Project (SEMP), and Harold (Hal) Balbach of the US Army ERDC
and CERL for their dedicated interest in and support of this project. Our sincere thanks to
Brian R. Chapman for reviewing a draft of this manuscript, Clayton Sublett for depositing
specimens within the Sam Houston State University Natural History Collections and database,
and Danté Fenolio for discussing (with W.I. Lutterschmidt) aspects of this natural
history observation.
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