Cooperative breeding the selection for information sharing among groupmates

Understanding variation in reproductive skew between and within cooperatively breeding species is a key aim of social evolution. However, tests of reproductive skew models give equivocal results, potentially because different models make different assumptions and some of the theoretical assumptions are wrong. Most models assume that both dominants and subordinates are perfectly informed, but animals likely have asymmetric imperfect information, since individuals know better their own quality and subordinates are freer to explore breeding options outside the group. To explore effects of dominants’ uncertainty, we extended the standard concession model of skew with an explicit focus on subordinate quality, which we assume determines their outside options and influences their contribution to group productivity. Depending on how quality influences group productivity, dominants should prefer low- or high-quality subordinates. When subordinate quality correlates positively and strongly with group productivity, skew decreases with quality, otherwise skew increases with quality. The average concession offered to subordinates is greatest when dominants have imperfect information. In most cases dominants are selected to acquire information, whereas subordinates should restrict the information given to dominants, even though this may reduce the opportunities for cooperative breeding. Concessions always decrease with relatedness, so related subordinates would especially benefit from the dominant being uncertain about relatedness, potentially explaining why true kin recognition is rare in nature. Overall, our new predictions show that uncertainty can strongly influence evolutionary games and that incorporating it in skew models may to help explain patterns of cooperative breeding observed between and within species.