Sexual selection in search of good genes : analysis of mate choice experiments and ecophysiological stress tolerance in Drosophila

Female preference for male ornament is favored by sexual selection. It is not clear whether the preference is limited to male ornament only or it is actually for genes that affect fitness of the upcoming progeny. In mating systems in which males provide direct benefits of fitness to the female or their offspring, the answer seems straightforward  females should prefer to mate with males that are able to provide more resources. We tested the hypothesis whether spotted and spotless males and progeny from sexually preferred males of Drosophila biarmipes vary in their levels of environmental stress tolerances. Our results showed that male flies with dimorphism for wing spot varied in their mating success and stress tolerance. Data have shown significant differences in mated pairs with spotted and spotless males. Spotted and spotless males also differ significantly in ecophysiological stress tolerance. Finally, females mating with a high-quality male (spotted wing) results in offspring with high performance. We found significant effects on fecundity of mated females and egg-to-adult viability of their progeny. Our results are consistent with good genes sexual selection and suggest that mate choice could provide indirect benefits to females. To the best of our knowledge, this is the first report on the ecological significance of wing color dimorphism in a species  Drosophila biarmipes.