Learning about prospective mates in male fruit flies: effects of acceptance and rejection

Abstract

Neurogenetic research in fruit flies (Drosophila melanogaster) has established numerous protocols that illustrate flies' rich behavioural repertoire as well as excellent learning and memory abilities. To place that information in an evolutionary context, we followed up on earlier studies by evaluating the effect of experience with a variety of relevant female categories on males' courtship behaviour. We found, for the first time, that the experience of mating with conspecific females caused males to subsequently show lower levels of courtship towards heterospecific females compared to control males. These courtship levels, however, were higher than those of males that had experienced rejection by heterospecific females. Courtship reduction was selective: males that mated conspecifically did not subsequently show low levels of courting other conspecific females, and males that were rejected by recently mated conspecific females did not show low levels of courting heterospecific females. Interestingly, males that mated with virgin conspecifics and males that were rejected by virgin heterospecifics subsequently showed similar levels of low courtship towards recently mated conspecific females, suggesting that males find mated females unattractive after encountering virgin females. Males, however, showed higher levels of courtship towards mated females after mating with simulated mated females than after mating with control virgin females. Overall, our results indicate that adaptive use of learning by male fruit flies enhances mating success and reduces time and effort pursuing relatively less desirable or attainable females.