Acoustic Repertoire and Calling Behavior of the Gliding Treefrog, Agalychnis spurrelli (Anura: Hylidae)

Abstract

Acoustic communication is essential for reproductive success in frogs. Males produce different types of calls to attract females, advertise territoriality or location in a chorus, or communicate with heterospecifics. Quantitative descriptions of amphibian calls provide basic information for taxonomic, ecological, evolutionary, and conservation studies. Here, we describe the acoustic repertoire of Agalychnis spurrelli and discuss this species' reproductive behavior on the basis of observations made over the course of a breeding season in May–December 2007. Males produced one type of advertisement call and two types of aggressive calls (calls A and B) that differed in temporal and spectral frequency. The advertisement call was a single note. Aggressive call A was a long-pulsed single note, and call B was composed of more than two notes per call. Calling behavior was influenced by chorus size and male-to-male proximity, with males altering their advertisement calls with the increase of chorus size and eventually producing aggressive calls. These results suggest that A. spurrelli might exhibit graded aggressive signaling, helping males to delimit their calling site and reducing the number of agonistic encounters.