Responsiveness to sound temporal features at realistic signal presentation rates in a temperate austral forest frog, Batrachyla leptopus (Batrachylidae)

Evoked vocal responses of male frogs are quite selective for temporal features contained in conspecific calls. However, responses to sound features not contained in natural vocalizations can also elicit evoked calling, indicating a relative broadness of acoustic recognition spaces. Former studies have shown that Batrachyla leptopus, a frog from the South American temperate forest, responds with calls of potential aggressive content to synthetic stimuli containing elements of such signals and also to novel signal features. The current study explores the vocal responsiveness to signals of diverse temporal structure under realistic conditions of stimulus broadcast, employing presentation rates observed in alternating interactions between pairs of males. The results show that aggressive patterns of response, measured as increased call duration, are specially consistent in exposures to stimuli of novel design, not related to natural vocalizations. These results stress the relevance of hidden recognition preferences, pre-existent perceptual biases and related processes to account for the extant acoustic responsiveness of sound communicating animals, contributing to assess the relevance of aggressive signaling patterns for the evolution of sound communication in anurans