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As in all advanced insect societies, colony-organization in honey bees emerges through a structured division of labor between essentially sterile helpers called workers. Worker bees are sisters that conduct all social tasks except for egg-laying, for example nursing brood and foraging for food. Curiously, aging progresses slowly in workers that engage in nursing and even slower when bees postpone nursing during unfavorable periods. We, therefore, seek to understand how senescence can emerge as a function of social task performance. The alternative utilization of a common yolk precursor protein (vitellogenin) in nursing and somatic maintenance can link behavior and aging plasticity in worker bees. Beneficial effects of vitellogenin may also be mediated by inhibitory action on juvenile hormone and insulin-like signaling., (Copyright 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)

Functionally sterile honey bee workers synthesize the yolk protein vitellogenin while performing nest tasks. The subsequent shift to foraging is linked to a reduced vitellogenin and an increased juvenile hormone (JH) titer. JH is a principal controller of vitellogenin expression and behavioral development. Yet, we show here that silencing of vitellogenin expression causes a significant increase in JH titer and its putative receptor. Mathematically, the increase corresponds to a dynamic dose-response. This role of vitellogenin in the tuning of the endocrine system is uncommon and may elucidate how an ancestral pathway of fertility regulation has been remodeled into a novel circuit controlling social behavior.