Secondary courtship songs and inhibitory songs of Drosophila virilis-group males.

The males of all Drosophila virilis-group species produce primary courtship song; and the males of four of these species also provide secondary courtship song when courting a female. The amount of secondary song and the courtship phase at which it is produced vary according to the species. D. lummei males produce secondary song consisting of successive 12-ms-long sound pulses with 70-ms-long intervals between pulses. D. borealis males produce short and dense pulse trains and D. littoralis and D. flavomontana males produce single sound pulses of a long duration (80-160 ms). The males of all species produce pulse-structured inhibitory song when they are courted by another male. In the secondary and inhibitory songs of interspecific hybrids, short and dense pulse trains of parent species break into pulse song with long interpulse intervals. This suggests that songs consisting of short and dense pulse trains and pulse songs with long interpulse intervals are just different modes of the same song. Sine songs (long sound pulses) seem to be inherited independently of pulse song.