Conditioned responses in courtship behavior of normal and mutant Drosophila

Male courtship behaviour in Drosophila melanogaster is modified by prior sexual experience. Whereas naive males nearly always court virgin females persistently, males previously paired with unreceptive fertilized females subsequently court virgin females in an abbreviated manner, if at all. The probability of diminished male courtship is directly related to the duration of the prior "conditioning" period with a fertilized female. Naive males court fertilized females less vigorously than they court virgins; this depression of male behavior occurs even if the male is blind or if the fertilized female cannot actively reject his courtship. These results suggest that fertilized females are a source of both courtship-provoking and courtship-inhibiting olfactory cues and that the central association of these cues in males is sufficient to bring about the retention of modified courtship behavior. Mutant "amnesiac" males, selected as memory-deficient in a learning test unrelated to courtship [Quinn, W. G., Sziber, P. P. & Booker, R. (1979) Nature (London) 277, 212-214], are trainable by exposure to fertilized females, but the experience-dependent behavior-diminished courtship performance-wanes abnormally rapidly-i.e., less than 1 hour, compared to 2-3 hr for wild-type flies.