Territorial behavior and vocal response in male Hyla arborea savignyi (Amphibia: Anura)

Calling males of the Israeli tree frog Hyla arborea savignyi maintain a distance of at least 30 em from one another. If a conspecific male comes closer the caller reacts aggressively or falls silent. These behavior patterns could also be elicited by simulated mating calls presented at an intensity corresponding to that of the calls of a male 30 em away. As the sound pressure of the simulated calls was progressively reduced, the test frog responded by shifting from territorial calls to mating calls. Simulated calls at relatively low intensity which elicited only mating calls evoked calls with the shortest latency when the pulse rate of the simulated signals corresponded to that of the natural mating call or was 20 pulses/s higher. The male frogs produced the greatest latency periods when stimulated with calls of Hyla arborea arborea. This result implies that the Israeli tree frog should be further studied as a possible separate species, Hyla savignyi.