1INRA Zoologie-Apidologie 84 914 Avignon cedex 9, France.
2Department of Entomology, University of Illinois, Urbana, IL 61801, USA.
Adult worker honey bees show age polyethism, a type of behavioral development that gives rise to an age-related division of labor in bee colonies. Young individuals perform tasks in the nest such as brood care and colony maintenance for the first 2-3 weeks of adult life and then forage outside the hive for remaining 1-3 weeks of their life. Age polyethism is not rigid; bees can accelerate, delay, or even reverse their behavioral development in response to changing colony needs. Plasticity in honey bee age polyethism is regulated, at least in part, by social factors: old bees inhibit the rate of behavioral development of younger bees. This inhibition requires physical contact between bees, suggesting that it is chemically mediated. We tested this hypothesis by determining whether chemical components of foragers extracted in polar and apolar solvents can delay behavioral development in young bees. Methanol and pentane extracts were administered in food given to small experimental colonies. Results for the pentane extracts support the hypothesis that social inhibition in honey bees involves chemical signals.