Vitellogenin plays a role in regulating honey bee swarming

Authors: KLETT, KATRINA - University Of Minnesota; Ihle, Kate; Simone-Finstrom, Michael; SPIVAK, MARLA - University Of Minnesota

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Honey bees are social insects, living in colonies made up of one queen, thousands of workers, and hundreds of drones. When a colony becomes large and crowded it splits, or reproduces, in a process called swarming. While much is known regarding the triggers of swarming, the physiological processes involved are largely unknown. In this two-year study we looked at how a biomarker like vitellogenin, a key protein involved in aging, egg production, nutrition, and stress resistance, relates to this process. We found that vitellogenin levels can predict the likelihood of a colony swarming as soon as three days prior to the event. Specifically, we found higher levels of vitellogenin in middle-aged bees (10-14 days old), compared with same aged bees from non-swarming colonies, indicating they are physiologically delayed in maturation, maintaining nurse-like characteristics. The delayed physiological shift in workers ensures the colony retains a robust population of young bees, which are vital for colony fitness during reproductive swarming both for those that swarm and those that are left behind. Our results may provide a missing link in the connection between physiological and environmental factors that lead to reproductive swarming in honey bees.

Technical Abstract: Swarming, or colony reproduction, in honey bees (Apis mellifera) is an indicator of colony-level fitness. The drivers of swarming remain elusive at both the colony and individual bee level. Floral abundance, rapid colony growth and congestion are colony correlates and partial triggers of swarming but are not singularly causal. The nutritional and physiological state of individual bees within colonies preparing to swarm has been understudied. We hypothesized that levels of vitellogenin, a hospholipoglycoprotein that influences the age-based division of labor in individual bees, might also mediate the cascade of physiological and behavioral processes that lead to reproductive swarming. Over two years, we compared vitellogenin levels in age-marked worker bees sampled at various intervals before the swarm (pre-swarming colonies) to samples of same-aged bees collected from non-swarming colonies at the same intervals. Vitellogenin levels were significantly higher in 10 and 14 day old bees from pre-swarming colonies three days prior and within 24 hr of swarm issuance. Vitellogenin levels normally decrease in 10-14d old bees that are transitioning to the forager behavioral state. We provide a hypothesis for how vitellogenin levels in individual bees might influence the colony-level regulatory processes that lead to swarming.