Abstract: Disease plays an important role in managing diversity; thus parasites (pathogenic microbes) are a fundamental aspect to consider when working with community interactions. Pollinators such as bees are well known for their importance in providing pollination services. In this study, we focus on determining what drives parasite prevalence in wild bee communities across a latitudinal gradient. We hypothesized that 1) bee abundance will result in an amplification of parasite prevalence as a result of increasing exposure to infected individuals, and 2) bee diversity will have a dilution effect on parasite prevalence due to hosts varying in their transmission abilities. Lastly, 3) we hypothesize that latitude will have an indirect dilution effect on parasitism through its positive effect on bee diversity. To test our hypotheses, we sampled bees and their interactions in meadows in the Madrean Sky Islands (Arizona/New Mexico), a group of isolated mountain meadows that serve as unique communities across a latitudinal gradient. We screened bees for seven common bee parasites using DNA extractions and sequencing. We used multilevel Bayesian models to determine the relationships between the layers of community interactions and parasite prevalence. We found that bee abundance consistently amplified parasitism, whereas bee diversity diluted only some parasites. As for the latitudinal gradient, we found latitude was positively related to floral diversity but not bee diversity. Our findings suggest that bee diversity can contribute to having a healthy bee community, but other factors still play a role in the prevalence of parasites in the community. Much is still unknown of the role these parasites have on wild bees.
