SECONDARY COURTSHIP SONGS AND INHIBITORY SONGS OF DROSOPHILA VIRILIS-GROUP MALES

The males of all Drosophila virilis-group species produce primary cour tship song; and the males of four of these species also provide second ary courtship song when courting a female. The amount of secondary son g and the courtship phase at which it is produced vary according to th e species. D. lummei males produce secondary song consisting of succes sive 12-ms-long sound pulses with 70-ms-long intervals between pulses. D. borealis males produce short and dense pulse trains and D. littora lis and D. flavomontana males produce single sound pulses of a long du ration (80-160 ms). The males of all species produce pulse-structured inhibitory song when they are courted by another male. In the secondar y and inhibitory songs of interspecific hybrids, short and dense pulse trains of parent species break into pulse song with long interpulse i ntervals. This suggests that songs consisting of short and dense pulse trains and pulse songs with long interpulse intervals are just differ ent modes of the same song. Sine songs (long sound pulses) seem to be inherited independently of pulse song.