Individual bumblebee foraging repertoires: Implications for disease persistence

Abstract Generalist species may be comprised of individual specialists. Individual specialization can impact disease transmission at shared resources by shaping contact patterns. Mathematical models of pollinator diseases that spread via flowers have shown that R 0 can be greatly amplified when each forager specializes on one flower species at a time with slow turnover. Yet, such behaviour has not been empirically demonstrated in generalist bumblebees. Here, we used palynology from sequential pollen loads of individual common eastern bumble bees ( Bombus impatiens ) to assess their foraging preferences over time. We used an automated monitoring system to greatly improve recapture rates, hence allowing a more complete characterization of each bee's foraging behaviours. Individuals in a bumblebee colony exhibited unique foraging repertoires of two to three flower species while the full‐colony diet breadth was up to three times larger depending on time of year. Individual repertoires exhibited roughly 50% turnover, on average, over 10 days. Implications for disease transmission when individual repertoire sizes are greater than one may differ from specialization on a single flower species. Hence, we developed mathematical models where each bee has an effective repertoire size of two, and found that ignoring individual specialization still resulted in an underprediction of R 0 , although to a smaller extent compared to a single‐specialty model. Our results provide novel insights into the foraging behaviours of social bumblebees and improve predictions of how diseases are transmitted and persist in complex plant–pollinator networks. Read the free Plain Language Summary for this article on the Journal blog.