| Frogs and toads use both acoustic and visual signals to communicate within their noisy, competitive breeding aggregations. In this thesis, I studied acoustic and visual signals in the Neotropical yellow toad, Incilius luetkenii, in Costa Rica. I provide the first quantitative description of this species' vocal behaviour, and I demonstrate that the spectral properties of male calls are correlated with body size; therefore, male calls may be used in size assessment. I experimentally demonstrate that chorus transmission distance is enhanced by the number of concurrently calling toads as well as the pitch of their calls; therefore choruses may attract more conspecific animals than a lone signaller. In terms of visual signals, I show that males respond more strongly to female-like brown models versus male-like yellow models; therefore colour facilitates sex recognition. My research expands our understanding of communication in a scramble competition mating system of an explosively breeding anuran. |
