No direct contact needed for drones to shorten workers lifespan in honey bee

Abstract

The honey bee, Apis mellifera, has been extensively used as a model in gerontological research, although the presence of adult males has been a factor so far neglected in investigations of the social regulation of worker aging. In the honey bee, drones (males) are produced and maintained only in the swarming season, or if a colony loses its queen. Here, we report on the longevity cost incurred by queenless workers that provide care for adult drones under conditions of food resources limited to hydrocarbons only. We found that the presence of drones reduced the life expectancy of workers, even if the workers were prevented from direct contact with the drones (double-mesh-type test). At the same time, the survival rate of the drones was surprisingly high. This suggests that our results reveal the existence of a mechanism that drones use to increase their fitness. We hypothesize that drones are able to communicate their presence to workers without direct contact. Alternatively, queenless workers might try to recruit other individuals to take care of males. In both cases, queenless workers, which are not able to reproduce themselves when deprived of protein, dramatically respond to the presence of drones.