A FUNCTIONAL ANALYSIS OF THE MATING CALLS OF THE NEOTROPICAL FROG GENERA OF THE LEPTODACTYLUS COMPLEX (AMPHIBIA, LEPTODACTYLIDAE)

Ian R. Straughan and W. Ronald Heyer

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Abstract: Functional characteristics or design features of mating calls for 19 species in the complex are given and analysed for patterns of relationship and convergences due to functional constraints. Two basic ' mating

call patterns can be defined. The first, a quiet, incessant popping produced by exploding a burst of air through the glottis usually with little amplification by secondary structures, is characteristic of riparian species that call resident females over short distances. The second call consists of a single tone burst (note) produced by passing a pulsed stream, of air through the glottis. Often a change in tension of laryngeal musculature produces frequency modulation through the note. In the latter call, resonance in the vocal sacs provides finer frequency tuning and better radiation of the call for attracting females over much longer distances. Patterns of structural similarities in calls are consistent with relationships based on morphology in some instances and apparently contradict morphological evidence in others, indicating that convergence in mating call characters may occur.