Influência de características acústicas e corpóreas em disputas agonísticas de Pithecopus nordestinus (Anura: Phyllomedusidae)

Abstract

Victory in agonistic encounters is usually accompanied by direct or indirect benefits to the winners, which contribute to their fitness. Morphological characteristics are important predictors of victory in aggressive disputes in many animal groups, but in anurans the acoustic communication plays an important role in the intrasexual interactions. Although the use of vocalizations is widely known as an intermediary of agonistic interactions, the influence of these chants on the success of physical disputes is still poorly understood in this group. The activity of vocalization requires a high metabolic expenditure, thus, males need to adjust the investment in vocalizations in order to maintain the level of competition and the energy expenditure. In this work, we evaluated how body size and the call influence success in agonistic disputes between male Pithecopus nordestinus anurans in a markedly seasonal environment (Caatinga stricto sensu). In addition, in order to contribute to the comprehension of the emission of each corner in context associated with the agonistic interactions, we evaluate how the proportion in which the calls are emitted occurs in different contexts of intrasexual interaction. We verified that length, body mass and condiction did not influence the success in agonistic disputes, as previously registered for the same species in humid forests. On the other hand, we find a positive relationship between aggressive call rate and victory in disputes. The proportion of Territorial call I increased with the reduction of the distance between males, and that of call decreased.We conclude that acoustic traits are important predictors of victories in agonistic disputes among males of P. nordestinus to the detriment of body size attributes and that modifications in the emission of calls occur in relation to different contexts of intra-sexual interaction.