Differential responses of avian and mammalian predators to phenotypic variation in Australian Brood Frogs.

J P Lawrence,Brice P Noonan,Michael Mahony,Lesley Joy Rogers

doi:10.1371/journal.pone.0195446

J P Lawrence, Brice P Noonan + Show 2 more

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https://doi.org/10.1371/journal.pone.0195446

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Abstract

Anti-predator signaling is highly variable with numerous examples of species employing cryptic coloration to avoid detection or conspicuous coloration (often coupled with a secondary defense) to ensure detection and recollection. While the ends of this spectrum are clear in their function, how species use intermediate signals is less clear. Australian Brood Frogs (Pseudophryne) display conspicuous coloration on both their dorsum and venter. Coupled with the alkaloid toxins these frogs possess, this coloration may be aposematic, providing a protective warning signal to predators. We assessed predation rates of known and novel color patterns and found no difference for avian or mammalian predators. However, when Pseudophryne dorsal phenotypes were collectively compared to the high-contrast ventral phenotype of this genus, we found birds, but not mammals, attacked dorsal phenotypes significantly less frequently than the ventral phenotype. This study, importantly, shows a differential predator response to ventral coloration in this genus which has implications for the evolution of conspicuous signaling in Pseudophryne.

Highlights

Phenotypic coloration and pattern in prey species often serves to evade or deter potential predators
Even aposematism may be observer-specific as modeling has demonstrated that conspicuous signals to avian predators may not be conspicuous to other predators
This study was conducted in the Watagans National Park (33 ̊03’S, 151 ̊20’E) in New South Wales in July 2015. This site was chosen because three Pseudophryne species have been recorded from the site (P. australis, P. bibronii, and P. coriacea)

Summary

Introduction

Phenotypic coloration and pattern in prey species often serves to evade or deter potential predators These signals range from cryptic (i.e., background matching; [1]) to conspicuous (i.e., aposematism; [2]) with some signals serving both functions [3,4]. Even aposematism may be observer-specific as modeling has demonstrated that conspicuous signals to avian predators may not be conspicuous to other predators (i.e., crabs and snakes [8]). The duality of these signals can result in phenotypes that are complex, and perhaps not readily apparent as to how species use signals

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