The evolutionary causes and consequences of mate preferences: experimental tests using the fruit fly drosophila serrata

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In sexual species in nature, it is common for individuals, generally females, to prefer certain males over others in their choice of mates. Such mate preferences can be costly to the female in many ways, potentially increasing her risk of predation, causing her to waste time that could be spent foraging, and even reducing her chances of mating at all. Such costs imply that females must also benefit in some way from mate choice, otherwise preferences would be selected against evolutionarily. Remarkably, however, mate preferences are common even in species where males contributes little to their mate, or their offspring, beyond their genes. Why do mate preference evolve under such conditions? A leading hypothesis is that some males are preferred over others because of their high genetic quality. The idea is that, by mating with these males, females ensure that their offspring receive these 'good genes'. Although the hypothesis is appealing, and mathematical models suggest it can occur, there is little experimental evidence in support of it. My research addresses both why mate preferences evolve and what their evolutionary consequences are for adaptation and the origin of new species. To do this, I use a species of fruit fly in which mate preferences are well understood and depend on a suite of chemicals, termed contact pheromones, found on the cuticle of the fly. I use these flies to conduct manipulative evolutionary experiments and quantitative genetic studies to test specific mechanisms by which mate preferences evolve and to understand their evolutionary consequences.