Entomological Society of America
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Behavioral predictors of and effects of parasites on colony initiation in bumble bees
Colony initiation is a key stage in the life cycle of many social insects. Bumble bees have an annual life cycle in which only queens overwinter and then initiate colonies in spring. Successful colony initiation is therefore critical for population growth of these important pollinators. However, the factors that determine colony initiation success or failure in bumble bees remain unclear. We collected gynes of three bumble bee species (Bombus huntii, B. griseocollis, B. nevadensis, B. appostus and B. occidentalis) in early spring after they emerged from their winter diapause but prior to nest initiation and brought them into the lab for observations throughout the colony initiation process. After daily feedings, we observed key gyne behaviors potentially indicative of colony initiation success, including: attempting escape, pacing, still, perched on eggs, eating pollen and eating nectar. We analyzed whether prevalence of these behaviors predicted probability of egg laying, larval development, and colony growth. We also measured mating status, and presence and prevalence of Nosema bombiandCrithidia bombi as additional predictors of colony initiation success. Preliminary analyses reveal differences among species in colony initiation. Parasite prevalence was suprisily high, explaining little of the variation in colony initiation success. A better understanding of the factors affecting colony initiation can not only inform our understanding of wild populations but can facilitate management of these critical pollinators.
Presenting Author: Ethan Rowe
Co-Authors: Michael E. Dillon, PhD