Dissection of the inputs necessary to produce associative and non-associative courtship conditioning. A. Ejima , L. Griffith. Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA.

   Unsuccessful courtship toward mated females reduces subsequent courtship levels of males in Drosophila melanogaster. This experience-dependent behavior modification is called "courtship conditioning" and is one of the classical paradigms of learning and memory in this organism. While it has been speculated that an aversive female pheromone gets associated with courtship during training, it is unclear what signals are really necessary for producing courtship suppression.
   In order to investigate the role of specific sensory inputs in this behavior, we employed artificial odorants, dim-red lights, decapitation and Acp70A^g.Yp1.hs (ypsp) transgenics to characterize the salient signals received by the male during conditioning. We found that 1) virgin females can be effective trainers when copulation is prevented during training and 2) an artificial olfactory stimulus (benzaldehyde) can be used as an associative cue to reduce subsequent courtship behavior. This suggests that the aversive pheromone of mated females is not a necessary component for courtship suppression. We also identified a female-type specific conditioning, which is a habituation-like response. In studies using virgin females as trainers, pre-test dishabituation did not disturb the memory acquired during training, indicating that the conditioning in this case does not result solely from habituation. Additionally, we found that the activity of trainer females enhanced the training effect, and that visual stimuli can act as a potent courtship stimulator that can overcome training in some lines. Comparison of the behavior phenotypes of olfactory mutants, the learning mutants dnc and amn, and transgenic flies expressing CaMKII or tetanus toxin revealed the importance of olfaction during the conditioning and the perceptive hierarchy during information processing.