Biotic and abiotic factors guide bumble bee (Bombus impatiens) pollen foraging preferences

Understanding foraging preferences of bee species is critically important for designing conservation projects that attract and sustain these vital community members. Unfortunately, fully characterizing bee host plant preferences and patterns of visitation to host plants has been challenging because many factors influence foraging decision-making. Moreover, determining preferences of generalist bee species is difficult because of their catholic tastes and floral resources are sensitive to spatiotemporal variability. Bee foraging preferences are particularly crucial for success of the species because the survival of subsequent generations depends on foragers’ ability to obtain resources of the appropriate nutritional value for larval development. To better understand patterns of floral visitation, we have used novel metrics to measure preferences of the bumble bee Bombus impatiens to seven perennial plant species native to central Pennsylvania. These metrics include time-of-day based observations of pollen foraging at scales of the community and individual bees, while simultaneously accounting for the number of available foragers in the environment and the differences in floral display of each plant species. Our results thus far indicate that B. impatiens exhibit predictable daily patterns in their pollen foraging choices. We hypothesize that these foraging preferences are correlated to the nutritional quality of floral resources. Accounting for circadian cycles of host plant visitation should be considered in future analyses to encourage precise interpretations of host plant preference and optimal bee conservation decisions.