The Mating Call of the Terrestrial Toad, Rhinella arenarum, as a Cue for Spatial Orientation and Its Associated Brain Activity

Abstract

Acoustic communication is essential for reproduction and predator avoidance in many anuran species. For example, mating calls are generally produced by males and represent a conspicuous communication signal employed during the breeding season. Although anuran mating calls have been largely studied to analyze content and phonotaxis toward choruses, they are rarely discussed as sources of information guiding spatial behavior in broader contexts. This is striking if we consider that previous studies have shown anurans to be impressive navigators. In the current study, we investigated whether terrestrial toad (Rhinella arenarum) males can use a mating call as a spatial cue to locate a water reward in a laboratory maze. Male toads could indeed learn the location of a reward guided by a mating call. This navigational ability, as indicated by c-Fos, was associated with greater neuronal activity in the telencephalic hippocampal formation (HF; also referred to in amphibians as medial pallium), the medial septum (MS), and the central amygdala (CeA). HF and MS are telencephalic structures associated with spatial navigation in mammals and other vertebrates. The CeA, by contrast, has been studied in the context of acoustic processing and communication in other amphibian species. The results are discussed in the framework of an evolutionary conserved, HF-septal spatial-cognitive network shared by amphibians and mammals.