Policing in queenless ponerine ants

Potential reproductive conflicts are common in insect societies. One proces s that can reduce or suppress conflict is policing. We review worker and "q ueen" policing in queenless ponerine ants. Queenless ants are an important model system for the study of intracolony reproductive conflict. Policing i s widespread in queenless ants because workers are totipotent, so that addi tional potential conflicts occur in comparison to species where workers can not mate, and these additional conflicts are frequently reduced by policing . Policing is more diverse than suggested by the examples known in other so cial insects. In almost all species of social Hymenoptera it can include pr eventing workers from reproducing by killing worker-laid eggs, but in queen less ants it can additionally include immobilisation or mutilation of worke rs attempting to reproduce by replacing the gamergate (i.e. mated worker wi th a queen-like role) or by becoming an extra gamergate. Policing by both w orkers and by the gamergate are important. Policing can be facultative. Dep ending on the age of the gamergate, workers can prevent her replacement by immobilising challenging workers or they can favour replacement by immobili sing the gamergate. The initial definition of policing was inspired by spec ies in which workers retain ovaries but cannot mate. We broaden the definit ion to include species, such as queenless ants, where females are totipoten t, thereby including not only conflict over male production but also over g amergate replacement and gamergate number. Finally, we compare policing wit h punishment and dominance hierarchy. Policing is not always punishment and it does not necessarily entail dominance relationships.