Light-affected male following behavior is involved in light-dependent mating in Drosophila melanogaster.

Abstract

Because the males of the Drosophila melanogaster species subgroup contributed to the light dependency of mating success and this was not due to the light-dependent nature of general activity, we have suggested that the light dependency of mating is caused by the light-dependent mechanism of male-specific sexual behavior. Courtship behavior of the wild type males of D. melanogaster was investigated in light and dark with a female partner with a severe norpA mutation. Total duration, frequency and bout length of all courtship elements, except for bout length of orientation and attempted copulation, were significantly lower in the dark than in light. Particularly, male following behavior was strongly affected by light. The sequence analysis of courtship behavior revealed that the courtship transition from orientation to following was severely disturbed in the dark. An unique transition from orientation to wing vibration, skipping the following phase was frequently observed in the dark. Under dim red light, single males showed a similar high locomotor activity in the dark as in light during the period over which male courtship behavior was investigated and analysed. It was suggested that the male following behavior requires visual cues and that the following is the major behavioral element involved in the light dependency of mating in Drosophila.