Wolbachia and its effects on mating preference in two Drosophila species

Kareena Collins, a students at the University of Maryland Eastern Shore, worked with Paul Ginsberg and Dr. Kelly Dyer.

Abstract: Wolbachia is a maternally inherited intracellular endosymbiont that can manipulate reproduction in many different species of arthropod hosts, enabling its invasion into novel host populations. The most common types of reproductive manipulation is cytoplasmic incompatibility (CI), where mating between an uninfected females and infected males results in embryonic mortality.  Two Drosophila species, D. recens and D. subquinaria, were used to investigate whether Wolbachia can affect mating preference in a native versus non-native host species. D. recens is the infected species of Wolbachia with a frequency ~ 98%, while D. subquinaria is the uninfected host of Wolbachia. In the geographic region where both species overlap there is gene flow between species. We introgressed Wolbachia from D. recens into D. subquinaria in the laboratory. Both species show the CI phenotype in the lab when there is a cross with an uninfected female and an infected male. We conducted no choice mate trials for all crosses among infected and uninfected individuals for each species (all intraspecific crosses), and watched for mating for a three hour observation period. We found that Wolbachia had no effect on mating preference in the native host, D. recens. However, in the non-native host, D. subquinaria, Wolbachia had a huge effect on mating preference, with a significant reduction of mating rate in the cross between an uninfected female and an infected male ( the “incompatible” cross). Because Wolbachia had such a significant effect on mating preference only in the non-native host of D. subquinaria, it has potential implications for Wolbachia’s inability to become established as a native host in the population and/or species.