COURTSHIP BEHAVIOR AND MATING SUCCESS OF WILD-CAUGHT DROSOPHILA-SILVESTRIS MALES

The courtship sequences of wild-caught Diosophila silvestris males paired with virgin females (the daughters of wild-caught females) were studied in the laboratory to examine behavioural characters affecting male mating success. Successful males courted the female persistently (without breaks) and spent more time in the head-under-wings position and in wing vibration than unsuccessful males. The relative durations of head-under-wings and wing vibration appeared to be consistent within males. Females were active and vigorous participants in courtship, contrary to the stereotype of female Drosophila being passive observers of male displays. The females could interrupt the courtship by flying away from the courting male, but they often returned to the male waving their wings. Receptive females waved their wings, and spent more time standing and less time preening than unreceptive females. After slashing at the male (or as a reaction to male circling) they stood still more often than unreceptive females. It appears that although receptive females do not have a particular signal that invariably indicates receptivity, they encourage male courtship throughout the sequence, by being active early, and standing still later. These results will serve as a baseline for comparisons with other species, and to stimulate experiments to examine female mating preferences.