Retinue attraction and ovary activation: responses of wild type and anarchistic honey bees (Apis mellifera) to queen and brood pheromones

Abstract

In most social insect colonies, workers do not attempt to lay eggs in the presence of a queen. However, in the honey bee (Apis mellifera), a rare phenotype occurs in which workers activate their ovaries and lay large numbers of male eggs despite the presence of a fecund queen. We examined the proximate mechanisms by which this ‘anarchistic’ behaviour is expressed. We tested the effects of brood and queen pheromones on retinue attraction and worker ovary activation using caged worker bees. We found no difference between the anarchistic and wild type queen pheromones in the retinue response elicited in either wild type or anarchistic workers. Further, we found that anarchistic queens produce a pheromone blend that is as effective at inhibiting ovary activation as the wild type queen pheromone. However, anarchistic workers are less inhibited by queen pheromones than their wild type counterparts, in a dose-dependent manner. These results show that the anarchistic phenomenon is not due to changes in the production of queen pheromones, but rather is due in part to a shift in the worker response to these queen-produced signals. In addition, we demonstrate the dose-dependent nature of the effect of queen pheromones on honey bee worker ovary activation.