Temporal selectivity of evoked vocal responses of Batrachyla antartandica (Amphibia: Leptodactylidae).

The advertisement call of the leptodactylid frog Batrachyla antartandica from southern Chile consists of a train of brief percussive tone pulses whose energy is centred at about 2 kHz. To gain an understanding of the temporal features that are essential for call recognition, playback experiments were conducted with 11 males. Subjects were presented with a synthetic imitation of this signal and variants for which different temporal call parameters were modified systematically. The number of pulses, pulse rate and latency of evoked vocal responses (EVRs) to stimuli having high pulse repetition rates (i.e. 8 and 16 pulses/s) were significantly weaker relative to responses to stimuli having an equal number of pulses but lower pulse rates. A similar, non-significant tendency was observed for a series of stimuli with different pulse rates for which the total stimulus duration was held constant. EVRs also decreased significantly for stimuli having long pulse durations (i.e. 48 and 96 ms) relative to stimuli comprising shorter pulses. No significant differences were observed between EVRs to stimuli for which pulse rise and fall times were varied from 1-20 ms. Responses to calls comprising trains of 10 pulses were weaker compared with stimuli having fewer pulses per train. The selective EVRs of B. antartandica for different temporal parameters contributes to an understanding of the mechanisms involved in call recognition and stress the relevance of temporal processing of sound by males for the emergence of specific patterns of vocal behaviour in anurans.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour