EAPSI: Investigating the Purpose of the Conspicuousness Coloration and its Relationship with Self-Synthesized Toxins in Australian Frogs

Lawrence Justin P, Oxford MS

Investigators

Abstract

Warning coloration (conspicuous coloration coupled with a negative consequence such as toxins) is a common defensive strategy throughout the animal kingdom. The best examples of warning coloration in vertebrates come from amphibians. Despite how common warning coloration is, little is understood about how it evolves and diversifies. Traditional evolutionary theory dictates that predator cognition should constrain diversification of warning signals, but a number of species exhibit a wide variety of signals both within and among populations. While collaborating with Dr. Michael Mahony (University of Newcastle) and Dr. Stephen Donnellan (University of Adelaide) in eastern Australia, this project will examine the evolution and diversification of conspicuous coloration in a group of small, toxic frogs (Pseudophryne). This project will elucidate 1) the purpose of conspicuousness coloration in this genus and 2) how predators can influence diversification of color signal in a group of Australian endemic frogs. By using clay models to mimic phenotypes found in Pseudophryne, this project aims to understand if 1) dorsal coloration acts as warning coloration, 2) ventral coloration acts as warning coloration or disruptive coloration, and 3) how predators generalize to color signals based on past experiences with local forms. Clay models will be placed on transects in areas where Pseudophryne are found to allow predators accustomed to local forms to prey upon models. Models will be placed either on natural or white backgrounds to determine if signals are warning coloration or not. Models will be collected and scored for type of predator attack based on dentition left in the plasticine clay. This will allow for the determination for what predators may be influencing color evolution in this group as well as how they react to novel signals. Pseudophryne are the only group of frogs that synthesize their own alkaloid toxins, which are common in other aposematic animals, but derived by diet. This research has implications for understanding how mode of toxin acquisition may influence the evolution of warning signals. Findings of this research will be applicable to a number of aposematic species around the world. This NSF EAPSI award is funded in collaboration with the Australia Academy of Scienc