Winebarger, M. M., M. W. Pugh & L. Siefferman

Experimental evidence for conspicuous coloration as a predator deterrent in Yonahlossee salamanders (Caudata: Plethodontidae). pp. 136-142.

Abstract. Amphibians are renowned for the variation in the colour and patterns of their integument, both within and between species. Some amphibian taxa are well known for using conspicuous coloration to signal their unpalatability to potential predators. Amphibian integument secretions contain biologically active compounds that are the source of unpalatability. Although the selective advantages are poorly understood, salamanders are often brightly coloured and secrete mucous-like substances that may serve physiological and defensive functions. In the southern Appalachians, two closely related species, the Yonahlossee salamander (Plethodon yonahlossee) and Northern grey-cheeked salamander (P. montanus), display vastly different coloration; yet, the signaling function of integument coloration is not well studied. While P. yonahlossee has a large red dorsal patch, P. montanus is uniformly grey which might indicate that there is a selective benefit of this dorsal patch. Here, we test the hypothesis that the red coloration of P. yonahlossee is an aposematic signal that communicates unpalatability to potential predators and predict that avian predators will avoid depredating this species. We used plasticine models of both species to experimentally test whether predators depredate conspicuously coloured models less frequently than dull models. Avian predation rates on grey models were significantly higher compared to that of red models, suggesting that the red dorsal coloration of P. yonahlossee is interpreted as a warning signal that deters predation. Future research should address whether P. yonahlossee is unpalatable or is effectively mimicking a sympatric aposematic species.

Key words. Amphibia, Plethodon montanus, P. yonahlossee, aposematism, anti-predator, integument, mimicry.