Avoidance response of a terrestrial salamander (Ambystoma macrodactylum) to chemical alarm cues.

Organisms from a wide variety of taxonomic groups possess chemical alarm cues that are important in mediating predator avoidance. However, little is known about the presence of such alarm cues in most amphibians, and in particular terrestrial salamanders. In this study we tested whether adult long-toed salamanders (Ambystoma macrodactylum) showed an avoidance response to stimuli from injured conspecifics. Avoidance of stimuli from injured conspecifics could represent avoidance of a chemical alarm cue or, alternatively, avoidance of a territorial pheromone or conspecific predator odor. Consequently, we also tested whether salamanders avoided stimuli from noninjured conspecifics. Salamanders avoided stimuli from injured but not from noninjured conspecifics. Therefore, we concluded that the response to injured conspecifics represents avoidance of a chemical alarm cue and not avoidance of a territorial pheromone or predator cue. This is the first clear demonstration of chemical alarm signaling by a terrestrial amphibian and the first report of chemical alarm signaling in an ambystomatid salamander. By avoiding an area containing stimuli from injured conspecifics, long-toed salamanders may lower their risk of predation by avoiding areas where predators are foraging.