Wolbachia incidence and prevalence in montane Lepidoptera

Animal hosts associate with endosymbiotic microbes that live inside their cells. Maternally transmitted Wolbachia bacteria are the most common endosymbionts, associating with about half of all insect species. Most Wolbachia form facultative associations with their hosts (i.e., the hosts do not require Wolbachia). In most systems, it remains unknown how common Wolbachia are within host populations and the extent to which their prevalence varies through time and space. Here, I fill this gap in knowledge by quantifying the incidence and prevalence of Wolbachia in a community of understudied montane moths. We conducted field sampling of divergent moth species every two weeks between May and August of 2024 at three sites: Rattlesnake Wilderness (Montana), Jocko Canyon (Montana), and Packard Meadows (Idaho). In total, we sampled about 2000 moths representing 40-50 species diverged about 80-150 million years ago. I predicted that Wolbachia prevalence would vary significantly among sampling locations and through time within locations. To identify Wolbachia in each individual, I extracted DNA and amplified the Wolbachia surface protein (wsp) gene using polymerase chain reaction. Using gel electrophoresis, I determined that Wolbachia prevalence varied temporally across the season (from 25% in May to 45% in August) and also spatially among the three locations (21% to 43%). I have currently screened 650 of my 2000 samples. My ongoing analyses focus on quantifying species-level variation in Wolbachia prevalence through time and space, which is critical to explain Wolbachia spread in nature and to inform applications that leverage Wolbachia for biocontrol of human diseases.