Do Green Treefrogs Use Social Information to Orient Outside the Breeding Season?

Gerlinde Höbel and Ashley Christie (2016) To decide efficiently where to forage, rest or breed, animals need information about their environment, which they may gather by monitoring the behavior of others. For example, attending to the signals of conspecifics or heterospecifics with similar habitat requirements may facilitate habitat choice. Such social information use seems taxonomically widespread, yet there is currently a dearth of information for amphibians. Anuran amphibians, with their highly developed auditory system and robust phonotaxis towards advertisement calls when searching for mates seem predisposed to use this hearing capability in other behavioral contexts. We conducted playback experiments to test whether anurans exploit acoustic signals in a non-reproductive context. In our experiments female Green Treefrogs did not show phonotaxis to signals associated with the presence of other frogs, and the orientation and speed of their movement was not different from animals randomly moving inside a silent arena. Previous studies documenting social information use in anurans have tested reproductively active frogs during the breeding season. By contrast, our study examined non-reproductive animals, and these did not approach social signals. We propose two non-exclusive hypotheses for this observed difference in phonotaxis behavior: (1) attending to social signals is restricted to ecologically most relevant time periods in a frogs life (i.e., finding breeding sites during the mating season), or (2) the ability of acoustic signals to stimulate the auditory system may be influenced by hormone levels regulating the reproductive state.