Male fruit flies learn to avoid interspecific courtship

Experimental data suggest, and theoretical models typically assume, that males of many fruit flies (Drosophila spp) are at least partially indiscriminate while searching for mates, and that it is mostly the females who exert selective mate choice, which can lead to incipient speciation. Evidence on learning by male D. melanogaster in the context of courtship, however, raises the possibility that the initially indiscriminate males become more selective with experience. I tested this possibility by comparing the courtship behavior of male D. melanogaster experienced at courting females of the closely related species, D. simulans, and inexperienced males. I found that compared with the inexperienced males, the males experienced with courting D. simulans females showed significantly lower courtship toward female D. simulans. Both male treatments, however, showed virtually identical courtship durations with female D. melanogaster. These results indicate that male fruit flies adaptively refine their courtship behavior with experience and suggest that the males contribute more to assortative mating and incipient speciation than is commonly assumed.