Currently I am focusing on anuran signal repertoires. Species vary widely in the complexity of their behavioral repertoire, including the number and elaboration of signals used for communication. I am interested in scoring a range of frog species for the size of their signal repertoire, in investigating the behavioral contexts in which different signal types are used, and in looking whether there are signal design features typically associated with specific call types. |
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Fig. 1: Vocal repertoire of the Gladiator frog Hyla rosenbergi. Gladiator frogs from Costa Rica have a fairly large repertoire, consisting of a courtship call, 1-, 2-, and 3-note advertisement calls, and two types of aggressive calls (Höbel 2000). The repertoire also includes one additional call type that was emitted by males when being separated from the female they were amplexing. Whether this vocalization was a startle responses (distress calls) or a call indicating non-receptivity (release calls) could not be determined |
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Building on this research, I am interested in investigating the effect that life history and mating system structure may have on the evolution of repertoire size and complexity. Since communication is by default a social behavior, the social environment in which communication takes place may influence the complexity of a species signal repertoire. The interactions a species encounters are largely determined by its mating system. Differences in the duration of the mating period, the densities of mates and rivals, and the resulting intensity of sexual selection, may lead to differential selection on mate attraction or territorial defense signals which in turn may lead to increased repertoire size or signal elaboration. |
In the past my research has focused on the effects of conspecific as well as heterospecific signal interference that occurs when animals communicate in close proximity to each other, for example in a chorus setting. In this context I have looked at the effect of call interference on female preferences and male call timing behavior in Green tree frogs (Hyla cinerea).
I have also investigated the effects of maladaptive hybridization with a close relative (H. gratiosa) on the evolution of the communication system of Hyla cinerea, documenting reproductive character displacement in female preference for the conspecific call. This research was conducted in colaboration with Dr. Gerhardt and Dr. Ehret)
In addition I have worked on the reproductive biology of neotropical gladiator frogs (in colaboration with Dr. Ehret), the natural history and bioacoustics of rain frogs, and geographic variation of communication signals in tree frogs and dart-poison frogs (in colaboration with Dr. Pröhl).
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