Crossing the taxonomic divide: conflict and its resolution in societies of reproductively totipotent individuals

Reproduction in groups may be unequal, with one or a few individuals monopolizing direct reproduction assisted by nonbreeding helpers. In social insects this has frequently led to a pronounced queen-worker dichotomy and a loss of reproductive totipotency among workers. However, in some invertebrate and all vertebrate societies, all or most individuals remain reproductively totipotent. In these groups, conflicts of interest over reproduction are potentially greatest. Here, we synthesize previous analyses of reproductive conflict, aggression and breeder replacement in haplodiploid societies of totipotent individuals and extend them to cover diploid (vertebrate) examples. We test predictions arising from this approach using the best-studied invertebrate (Dinoponera queenless ants) and vertebrate (naked mole-rat, Heterocephalus glaber) examples, although in principle our analysis applies to all similar groups. We find that premature replacement of a parent breeder by nonbreeders (overthrow) is rare. Dominant coercive control of nonbreeders by the breeder is often unnecessary and honest signalling of breeder vitality can maintain group stability and resolve conflicts over reproduction. We hope that by providing an explicit transfer of social theory between ants and naked mole-rats we will stimulate further cross-taxonomic studies that will greatly broaden our understanding of sociality.