Learning in the context of sexual behaviour and danger in female and male Drosophila pseudoobscura

Abstract

Learning in the context of mate choice is important because it can influence sexual selection and incipient speciation. While fruit flies (Drosophila spp.) have been a key model system for research on sexual selection, speciation and learning, much of the research on fruit fly learning in the context of sexual behaviour has focused on males even though females typically control mating decisions. In a series of experiments, we found no evidence that early experience with either only conspecific males or both conspecific and heterospecific males affected the frequency of heterospecific matings by female Drosophila pseudoobscura. We conducted further experiments to place our results in perspective. First, we tested whether heterospecific matings do not induce female unreceptivity and thus have little cost, in which case learning would be of little benefit. Contrary to our prediction, we found that females that had initially mated heterospecifically remated conspecifically at a lower frequency than females that had first mated conspecifically. Second, we replicated earlier data indicating that male D. pseudoobscura that are rejected by heterospecific females later selectively reduce courtship of heterospecific females. Finally, we tested whether females can learn as well as males in a nonsexual context involving learning to avoid odours associated with danger and found similar learning scores in females and males. Our results indicate that, in spite of the potential benefits from learning in the context of mate choice and possessing a good learning ability in another domain, female D. pseudoobscura either do not learn about potential mates or such learning is not as robust as it is in the males.