Meeting Abstract
Geographic variation examines phenotypic variation as a result of environmental changes along a geographic gradient. Host availability across a geographic range can affect host plant preference in herbivorous insects that rely on plants for feeding and breeding. The cactophillic fly Drosophila mojavensis is an interesting model in which to study geographic variation, as it is comprised of four geographically isolated populations. Each population specializes on a different host cactus despite the host cacti at times having overlapping ranges and uses the distinct odorants emitted by the cactus to identify their appropriate host plant. Here, we examine the effect of host availability on the peripheral olfactory system within and between D. mojavensis populations. We measured electrophysiological responses of odorant receptor neurons to single cactus volatiles and show intrapopulation differences in specificity and sensitivity of olfactory receptor neurons to cactus volatiles. This suggests that the peripheral nervous system has changed in response to host availability and these changes could play a role in differentiating between host cactus species.
