PARENT OFFSPRING CONFLICT AND THE RECRUITMENT OF HELPERS AMONG BEE-EATERS

GENETIC conflicts of interest are to be expected between individuals in any non-clonal society 1-5. One well studied form of conflict is that between parents and their offspring over the amount of parental care provided to the offspring 3. A very different manifestation of parent-offspring conflict may occur in certain cooperatively breeding species in which parents (breeders) are assisted in the rearing of young by their grown offspring (helpers) 6-8. If helpers have a sufficiently large effect on reproductive success, breeders will enhance their own inclusive fitness more by retaining their offspring as helpers than by allowing them to reproduce on their own 4,5,9. We report here that older male white-fronted bee-eaters (typically fathers) actively disrupt the breeding attempts of their sons, and that such harassment frequently leads to the sons joining as helpers at the nest of the harassing father. Calculation of fitness costs and benefits to the various participants helps to clarify both why parents engage in such 'recruitment' behaviour and why sons frequently do not resist.