Structure of the mating calls and relationships of the European tree frogs (Hylidae, anura).

As an extension of earlier investigations, the mating calls ofHyla arborea kretensis, Hyla a. molleri, andHyla a. sarda were studied, and variations in the calls with air temperature were determined. The mating calls of these species exhibit the typical structure, made up of short pulses of varying amplitude. The call duration and the inter-call interval decrease linearly with increasing temperature (over the range in which calls can occur), whereas the number of pulses per call does not change. Comparisons of the structure of the mating calls make it possible to assess the relationships among the European tree frogs, which so far have been regarded as subspecies of just one species.Hyla meridionalis represents a valid species; this is certainly also true ofHyla a. savignyi of the Middle East.Hyla arborea arborea andHyla a. sarda can be considered as subspecies, whereasHyla a. kretensis andHyla a. molleri cannot.