Sex with Other Males and Mated Females

Males without a gene called Gr32a, the gustatory receptor gene, showed normal levels of courtship with virgin females. But in competition with normal (or wild-type) males, they were outperformed by 4 to 1. In fact, the Gr32a-lacking flies courted the male competitors in addition to the females. The scientists also found that the males lacking the Gr32a gene courted females who had already mated. Wild-type males, however, were significantly less attracted by mated females, because mated females have received male pheromones during the first mating. The hapless Gr32a-negative males tried to mate with virgin females even when they had been covered with male pheromones, behavior that the wild-type flies avoided."This gene was very powerful for distinguishing between genders and for determining mating status," said co-author Tetsuya Miyamoto, Ph.D., also of the Department of Molecular Genetics and Microbiology. "Male pheromone is so effective that Gr32a mutants court males with almost the same intensity as they do females."The GR32a gene is not found in humans. "In general, the development of pheromones in human sexual behavior is not as clear-cut as one would hope," Amrein said. " So I think it is very difficult to make any direct connections between these gene findings in fruit flies and what happens in people."(read more...)