The role of early experience in the development of acoustic mating behaviors of Physalaemus pustulosus

Acoustic signals are used for communication in a variety of social contexts. Signals and receiver responses can vary, and that variation can come from development processes, physiological factors, or cognitive processes such as learning. The process of learning encompasses social learning, sexual imprinting, and vocal learning, among others. The development of acoustic behaviors has not been studied in anurans, one of the model systems for acoustic communications. This study examines the contribution of early experience in the development of the acoustically linked mating behaviors in Physalaemus pustulosus. I reared frogs from tadpole stage through metamorphosis to sexual maturity in four treatments -- conspecific chorus, heterospecific (P. enesefae) chorus, isolation, and noise. I then measured the advertisement calls of males, mate choices of females, and vocal responses of males. The male calls differed slightly with early experience; males who were reared in isolation produced shorter calls that were less attractive to females than species typical calls. In phonotaxis tests, female mate choices showed no effect of early experience. The vocal responses of males to acoustic stimuli showed the largest effect of experience. Males who were reared hearing a chorus of congeners, P. enesefae, increased their overall rate of calling and the production of complex calls when presented with a P. enesefae stimulus. By contrast, in the same test, males from other rearing groups showed either little increase or a decrease in calling activity. These findings support the prediction that female behaviors are less subject to environmental influence than are male behaviors. This research suggests that environment may play a role in the variation of male anuran behaviors and highlights the need for more research on the interaction of genes and environment in the development and variation of anuran mating behaviors.