Treefrogs with distinct advertisement calls produce similar territorial signals

Abstract

ABSTRACT The advertisement call contains important spectral and temporal information for species-specific recognition and is generally related to sexual attraction. On the other hand, the territorial call is emitted to defend a specific territory from conspecifics or heterospecifics. Therefore, we hypothesised that the territorial call of sympatric and close related species is more similar to each other (as a result of convergence or lack of divergence) than their advertisement calls. In order to test this hypothesis, we examined the territorial and advertisement calls of five anuran species of the genus Scinax. These species are sympatric and two of them were previously observed displaying heterospecific territorial communication. We redescribed the advertisement and territorial calls of these five species, compared them with cluster analyses and found that acoustic characteristics of the territorial calls were more similar to each other than that of their advertisement calls. These results could be indicative of a convergent selective pressure for the territorial call in opposite to a divergent selective pressure for the advertisement call. This pattern may be more widespread than reported and future directions are proposed.