Herpetology Notes, volume 9: 227-228 (2016) (published online on 25 October 2016)
Necrophagy (scavenging) on Cambarus robustus (Crustacea: Cambaridae) by the Black-bellied salamander Desmognathus quadramaculatus (Caudata: Plethodontidae) in the Appalachian mountains of North Carolina, southeastern USA.
Shem D. Unger*
There are many examples of facultative scavengers on 9 September 2016 in a tributary of the French Broad across vertebrate taxa which will readily consume River, Transylvania County, state of North Carolina, carcasses when available (DeVault and Rhodes, 2002). United States (35.261985°, -82.887734°; Altitude c.a. However, data is lacking regarding scavenging by 961 m a.s.l.). During the observation of the scavenging amphibians, including Desmognathus salamanders event, one individual D. quadramaculatus (TL = which can comprise a significant portion of vertebrate ~110 mm) initially investigated the dead crayfish, of biomass (recorded population density up to 14.69 which it subsequently bit off a small portion without m2) in the Appalachians (Crawford and Peterman, fully consuming it (Fig. 1 A). Within approximately 2013). Therefore, this note reports on necrophagy, 5 minutes, a live C. robustus approached the dead C. or scavenging (consumption of dead animal carcass) robustus to presumably scavenge the carcass (Fig. 1 B), by a Desmognathus salamander, which has yet to but after an additional 2 minutes retreated under a rock be documented to my knowledge in the scientific when a larger D. quadramaculatus (TL = ~140 mm) literature. approached the deceased crayfish and consumed it in its The plethodontid salamander, Desmognathus entirety within approximately 3 minutes (Fig. 1 C). quadramaculatus (Holbrook, 1840) is a large, aquatic Use of chemosensory chemical cues to detect prey is salamander within the genus Desmognathus, which can well documented in plethodontid salamanders, however be locally abundant in well-aerated small to medium little is known regarding the extent of scavenging by sized streams in hardwood forests across the Appalachian amphibians within streams. Many more species of mountains of North Carolina (Petranka, 1998). The diet Desmognathus exists, therefore scavenging could be of the Black-bellied salamander includes primarily much more widespread throughout the Appalachians aquatic and terrestrial insects as well as crayfish (Davic, Mountains. Moreover, the observation of the living C. 1991; Watson et al., 2005). Larger adults of similar robustus crayfish investigating its deceased conspecific Desmognathus salamanders have been reported to indicates that both crayfish and plethodontid salamanders consume not only crayfish but even other salamanders are able to successfully detect carcasses most likely (Bernardo, 2002; Felix and Pauley, 2006) and actively by chemosensory detection, yet relatively larger forage at the edge of the stream (Mills, 1996). Desmognathus potentially act as dominant, effective I observed multiple individuals of D. quadramaculatus scavengers in mountain streams. The preference of feeding on a recently deceased Cambarus robustus Desmognathus for the crayfish carcass and not the (Girard, 1852), within ~0.5 meters of the stream bank live crayfish, indicate Desmognathus are opportunistic scavengers on dead crayfish. This note documents the relatively rapid detection of dead prey items, followed by investigations of the carcass by both conspecific live crayfish and consumption by multiple individual D. Department of Biology, Wingate University, Wingate, North quadramaculatus salamanders, illustrating an important Carolina 28174, USA ecological interaction within Appalachian stream *Corresponding author e-mail: [email protected] systems that warrants further study. 228 Shem D. Unger
Appalachian mountains. Journal of Herpetology 47(4): 580– 584. Davic, R.D. (1991): Ontogenetic shift in diet of Desmognathus quadramaculatus. Journal of Herpetology 25 (1): 108–111. DeVault, T.L., Rhodes, O.E. (2002): Identification of vertebrate scavengers of small mammal carcasses in a forested landscape. Acta Theriologica 47(2): 185–192. Felix, Z.I., Pauley, T.K. (2006): Diets of sympatric Black Mountain and Seal Salamanders. Northeastern Naturalist 13 (4): 469– 476. Mills, G.R. (1996): A study on the life history and seasonal foraging habits of the salamander Desmognathus quadramaculatus Holbrook, in West Virginia. Unpublished Master’s thesis, Marshall University, Huntington, West Virginia. Petranka, J.W. (1998): Salamanders of the United States and Canada. Washington, USA, Smithsonian Institution Press. Watson, M.B., Pauley, T.K., Camp, C.D. (2005): Desmognathus quadramaculatus: Black-bellied salamander. In: Amphibian declines the conservation status of United States species, p. 723–726. Lannoo M.J., Ed., Berkeley, USA, University of California Press.
Figure 1. A) A smaller Black-bellied salamander Desmognathus quadramaculatus investigating a Cambarus robustus crayfish carcass, B) a live C. robustus crayfish investigating conspecific carcass of C. robustus prior to consumption by C) larger D. quadramaculatus salamander. All photos by author taken in Transylvania County, State of North Carolina, southeastern USA.
References
Bernardo, J. (2002): Natural History Notes: Desmognathus carolinensis (Carolina Mountain Dusky salamander) and Plethodon welleri (Weller’s salamander); Desmognathus monticola (Seal salamander) and Desmognathus wrighti (Pygmy salamander), Gyrinophilus porphyriticus (Spring salamander) and Desmognathus ocoee (Ocoee salamander). Intraguild Predation. Herpetological Review 33:121. Accepted by Cynthia Prado Crawford, J.A., Peterman, W.E. (2013): Biomass and Habitat Partitioning of Desmognathus on wet rock faces in the southern