Meeting Abstract
40.4 Sunday, Jan. 5 08:45 Call polymorphism mediates assortative mating between genetic morphs in an Amazonian frog GUERRA, M.A.*; CANNATELLA, D.C.; RYAN, M.J.; University of Texas at Austin; University of Texas at Austin; University of Texas at Austin m.guerra@utexas.edu
Theory predicts the importance of sexual selection in driving speciation processes. Empirical studies supporting this phenomenon, however, are far less common, and these are usually confined to comparisons among allopatric populations. This study empirically tests the potential of sexual selection to drive genetic and call differentiation in natural allopatric and sympatric populations of the Amazonian frog Physalaemus petersi. Male frogs use advertisement calls to attract females to breeding sites, and females use the calls to identify and discriminate among conspecific males. Acoustic characteristics of male calls in P. petersi vary among populations. Call analyses from several populations of the Ecuadorian Amazon has led us to classify them into three possible call morphs (based on the complexity and the dominant frequency of the males’ calls). This call polymorphism also coincides with a genetic polymorphism. Populations of different call morphs can be allopatric, sympatric and even syntopic. Signal variation is crucial to achieve behavioral reproductive isolation, but this variation must also be salient to females. The goals of this study are: 1) to test female discrimination ability and strength of selection, and 2) to assess the degree of assortative mating by call morphs (and thus genotypes) in nature. We performed female choice phonotaxis experiments in an allopatric and a syntopic population of P. petersi using one of the call morphs. Our results show that females discriminate mainly based on the dominant frequency of the male’s call, and female discrimination is the same regardless of the presence of other call morphs in the area. Also, we report the degree of assortative mating found in nature. This study highlights the significance of sexual selection in reproductive isolation.
