Regulation of Chorusing in the Vibrational Communication System of the Leafhopper Graminella nigrifrons1

Abstract

Male Graminella nigrifrons participate in alternating choruses. Vibrational calls emitted by males consist of three sections (S1, S2, and S3) that differ in pattern of amplitude modulation. In this study we examined the response of single males to synthetic choruses and to isolated call components to gain insight into the regulation of chorus structure. Males initiated calls primarily during the silent periods within synthetic choruses. In all 15 trials the number of overlapping calls and the duration of overlap was significantly less than expected if males call at random. Playback of S2, S3, or random noise while males emitted S1 caused males to interrupt calling, whereas males continued to call when S1 or no signal was played. In a related experiment, we played S2 or no signal while males were beginning to emit the S1, S2, or S3 phase of their calls. In response to this playback the duration of S1 and S3 was reduced, but the duration of S2 was not affected. These results suggest that an inhibitory-resetting mechanism may result in alternation of calls in this leafhopper.