Kin recognition via phenotype matching in a cooperatively breeding cichlid, Neolamprologus pulcher

Cooperatively breeding groups are often made up of a mixture of related and unrelated individuals. In such groups, being able to identify and differentially cooperate with relatives can bring indirect fitness benefits to helpers. We investigated the kin recognition abilities of the cooperatively breeding African cichlid Neolamprologus pulcher, while controlling for familiarity between individuals. When given a choice of associating with unfamiliar kin or unfamiliar nonkin, juvenile N. pulcher spent significantly longer associating with kin. Although both chemical and visual cues were required to stimulate the fish, chemical cues were more important than visual cues in kin recognition in this species. As all stimulus fish were reared separately from the focal fish, we can also conclude that N. pulcher used phenotype matching rather than familiarity to assess relatedness to other individuals. Furthermore, when given the choice of associating with familiar over unfamiliar kin, N. pulcher showed no significant preference. Hence, relatedness rather than familiarity appears to be more important in the association preferences of N. pulcher. This is advantageous, particularly if familiar individuals within the cooperatively breeding group are not necessarily relatives. In highly social species such as N. pulcher, being able to recognize kin can bring fitness advantages through kin selection and inbreeding avoidance.