View Program - 63rd Annual Drosophila Research Conference

The absence of mating between groups of organisms is one criterion for the separation of species. There could be multiple reasons for this absence, including geographical, behavioral, and genetic causes. The fruit flies Drosophila sechellia and Drosophila simulans inhabit the same geographical space, the Seychelles archipelago, yet remain separate species due to considerably low levels of hybridization. Previous studies have shown that their lack of interspecies mating is due to male mate discrimination, and that this mate choice is made by discrimination against cuticular hydrocarbon (CHC) profiles, which are unique to the two species. Additionally, it has been shown that chemicals uniquely present in D. sechellia’s food source, Morinda citrifolia (eg L-DOPA), affects the expression levels of genes related to CHC production. Given the likely effects of these species’ differing diets, and more specifically their consumption of L-DOPA on their CHC profiles, and the importance of these profiles in male mate choice, we investigated the consequence of dietary L-DOPA on intraspecific and interspecific mating behaviors. Here we show that L-DOPA does affect mating behavior, and this is mostly seen in D. sechellia flies, those that regularly consume L-DOPA in the wild. These results reveal that mating seen among these flies in the wild is influenced by the presence of L-DOPA. Given this, L-DOPA should be included in laboratory studies regarding mating behavior to mimic the flies’ natural conditions. Including L-DOPA would create a more natural environment and lead to mating behaviors more like those produced in the wild, generating more accurate results. Our results could be indicative of complex interactions between the environment and the genetic basis of mating behaviors, and thus support motivations for more in-depth studies of the effect of L-DOPA on various genes and the overall CHC profiles of D. simulans and D. sechellia. This would further clarify the mechanisms of their speciation.

Effects of L-DOPA on D. simulans and D. sechellia Mating Behavior