Meeting Abstract
Ecological speciation is driven by divergent natural selection among populations that experience different local habitats. For herbivorous insects, such differences can be differences in host plant availability, and divergent selection can lead to reproductive barriers between populations. Drosophila mojavensis is a cactophillic fly composed of four populations, each specializing on a different cactus. The flies identify the appropriate cactus host by the unique odorants they emit, and this creates selection pressure on the tuning and sensitivity of olfactory senses. Thus, D. mojavensis is an ideal species in which to study the proximate mechanisms of reproductive isolation resulting from differences in local habitat. Here, we explore the evidence for ecological speciation via a host shift by examining peripheral olfactory systems of D. mojavensis, with the goal of understanding mechanisms underlying their host specialization. Response profiles of olfactory receptor neurons to host cactus odorants are found to be different between populations and are sex specific. Our findings suggest a host shift alters peripheral olfactory perception and may eventually lead to divergence between populations.
