Relationship between floral communities and Crithidia infection in pollinator communities

Access to high quality nutritional resources is often correlated with reduced disease prevalence. However, an organism’s ability to obtain sufficient nutrition to reduce pathogen infection depends on its surrounding community. Previous research has found that Asteraceae pollen reduces Crithidia bombi infection in Bombus impatiens by up to 98% compared to mixed pollen diets. However, it is unknown how the proportion of Asteraceae plant species in a pollinator habitat affects disease transmission, prevalence, and intensity in the pollinator community. We chose 20 pollinator habitats representing low, medium, and high proportion of Asteraceae species in the plant community. We will measure plant species richness and floral abundance to determine the proportion and abundance of Asteraceae and non-Asteraceae plant species in each habitat. We will observe plant-pollinator interactions to understand how network structure and plant community composition influence Crithidia prevalence and intensity in four abundant bee species. We hypothesize that plant communities with a higher proportion of Asteraceae species will have lower Crithidia pathogen loads across all species due to shared floral resource use, but that this relationship will depend on the size of the pollinator habitat. Our findings will help us understand how plant community composition and plant-pollinator interactions influence the relationship between bee nutrition and disease and provide recommendations for plant community composition of pollinator habitats.