A quantitative analysis of behavioral selectivity for pulse rise-time in the gray treefrog, Hyla versicolor.
The selectivity of female phonotactic responses to synthetic advertisement calls was tested in choice situations. Preferences based on differences in the linear rise-time of synthetic pulses depended on intensity and carrier frequency. When the carrier frequency was 1.1 kHz, simulating the low-frequency peak in the advertisement call, females preferred alternatives with slower rise-time pulses that differed by 5 ms at playback levels of 75 dB SPL and higher. A rise-time difference of 10 ms was discriminated at 65 dB SPL. When the carrier frequency was 2.2 kHz, simulating the high-frequency peak in the call, females discriminated a 5-ms difference in rise-time only at 85 dB SPL. Females showed no preference when the difference was 10 ms at lower playback levels. The difference in the thresholds (about 15-20 dB) for discriminating differences in rise-time at the two carrier frequencies was greater than the difference in behavioral thresholds for these two frequencies (about 10 dB). This result suggests that rise-time discrimination can be mediated solely by the neural channel mainly tuned to the low-frequency peak in the call. Females probably assess differences in rise-time by comparing the first few pulses of each call rather than by averaging over the entire call.
Gerhardt
H C
HC
Division of Biological Sciences, University of Missouri, Columbia 65211, USA. gerhardth@missouri.edu
Schul
J
J
D000819:Animal Communication; D000818:Animals; D001001:Anura / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D002755:Choice Behavior; D005260:Female; D010897:Pitch Discrimination / Q000502:physiology; D014110:Touch / Q000502:physiology; D014828:Vocalization, Animal / Q000502:physiology*