Assistant Professor University of Minnesota Minneapolis, Minnesota
Parasitoid wasps are abundant, diverse, highly specialized members of many ecological communities. Like numerous other arthropods, parasitoid wasps are often infected with a maternally transmitted intracellular bacterium: Wolbachia. In Wolbachia-insect interactions: the line between mutualist and parasite is fuzzy: females infected with Wolbachia have a fitness advantage over others in the population, but at a cost. In many Wolbachia-infected parasitoid wasps, the cost is the transition to asexual reproduction in which females are produced from unfertilized eggs, a transition that often becomes permanent. Even though Wolbachia-mediated asexuality was discovered more than 30 years ago, the genetic mechanisms behind this phenotype have remained unknown. We used a suite of genomic, computational, and molecular tools to identify and characterize the genetic players from wasp host (Trichogramma pretiosum) and Wolbachia, that mediate the transition to asexuality. We find that Wolbachia infection and reproductive manipulation result in parallel transcriptomic and epigenetic changes in the wasp. Furthermore, we identified two candidate Wolbachia genes which are likely inducing this switch in wasp reproduction, and share new data on their role in parasitoid biology. Not only is the conversion to asexuality a significant contributor to altered evolutionary dynamics in parasitoid populations, but increases in the production of female wasps has direct implications for the deployment of biocontrol programs.
