Worker reproduction in honey-bees (Apis) and the anarchic syndrome: a review

Honey-bees, Apis, are an important model system for investigating the evolu tion and maintenance of worker sterility. The queen is the main reproductiv e in a colony. Workers cannot mate, but they can lay unfertilized eggs, whi ch develop into males if reared. Worker reproduction. while common in queen less colonies, is rare in queenright colonies, despite the fact that worker s are more related to their own sons than to those of the queen. Evidence t hat worker sterility is enforced by 'worker policing' is reviewed and worke r policing is shown to be widespread in Apis. We then discuss a rare behavi oural syndrome, 'anarchy'. in which substantial worker production of males occurs in queenright colonies. The level of worker reproduction in these an archic colonies is far greater than in a normal queenright honey-bee colony . Anarchy is a counterstrategy against worker policing and an example of a 'cheating' strategy invading a cooperative system.