No evidence for kin selection as an explanation for social group formation in clown anemonefish.

Social groups in which some individuals forgo reproduction and others reproduce, are one of the most remarkable products of evolution. To fully understand these social groups, we must understand both why non-breeders tolerate their situation and why breeders tolerate non-breeders. In general, breeders tolerate non-breeders because they help provision the breeders' offspring or the breeders themselves, but in some vertebrate societies the benefits that breeders accrue from non-breeders are surprisingly hard to detect.