Breeder-Helper Conflict in a Cichlid Fish With Broodcare Helpers: an Experimental Analysis

Abstract

AbstractThis paper reports an experimental analysis of conflicting interests in the cooperatively breeding Lamprologus brichardi (Cichlidae). Helpers clearly prefer to stay in the family territory rather than leave for an aggregation of same-size young or for an unoccupied area-even when their chances of reproducing independently are superior to those in the field. Helpers usually attain independence when the breeders force them to leave the territory. Breeders' toleration of helpers depends on the stage in the reproductive cycle, the size of helpers and the need for helpers. Large, previously expelled helpers are reaccepted when competition is increased. In these circumstances breeders prefer their own former helpers to strange young. Experimental and field evidence suggests that 3 factors are ultimately important for the breeder/helper relationship: reproductive parasitism by mature helpers, eventual cannibalism on breeders' eggs and competition for shelter within the territory. A graphical model shows how the initially common interests of breeders and helpers develop divergently when helpers reach the size at which they become sexually mature and less susceptible to predation. Large helpers pay to stay. The relationship of breeders and large helpers meets the criterion of reciprocal altruism.