The Evolution of Acoustic Signals of Frogs: Origins, Phylogenetic Information, Rates of Diversification, and Morphological Correlates

University Of Texas At Austin, Austin TX

Investigators

Abstract

9981631 Cannatella, Hillis, and Ryan The proposed research will integrate an important communication system, the advertisement call of frogs, with a phylogenetic approach in order to address the origin of frog vocalization, the rates of change in behavioral characters associated with vocalizations, and correlation of laryngeal shape change in the anatomical structures that produce the sounds. A formerly accepted phylogeny of frogs suggests that the earliest frogs did not have a well-developed acoustic signaling mechanism. According to a more recent hypothesis, the earliest frogs would indeed have had a well-developed communication system. These two alternative scenarios will be tested using more complete samples of species of the primitve frogs and larger samples of characters, from DNA sequences. There is a general bias that behavioral characters are more subject to change than other classes of data. The presence of intense sexual selection on the male vocal signal suggests that the footprint of history may be obliterated by rapid evolution of call characters. Thus, estimates of phylogenetic relationships derived from call characters will be very different from those derived from DNA sequences. The generality of this observation will be tested using complete DNA sequences of selected genes for five groups of frogs widely distributed throughout North, Central, and South America.