DOI 10.1007/s10071-008-0154-3ORIGINAL PAPER Smells like sib spirit: kin recognition in three-spined sticklebacks (Gasterosteus aculeatus) is mediated by olfactory cues

Abstract The ability to recognise kin has been demon-strated in several animal species. However, the mechanisms of kin recognition often remain unknown. The most fre-quently discussed sensory modalities to recognise kin are visual, olfactory and acoustical cues. Three-spined stickle-backs (Gasterosteus aculeatus) are able to diVerentiate between kin and non-kin when presented visual and olfac-tory cues combined. To elucidate, which cues they use to recognise kin female sticklebacks were given the choice between two identical computer animations of courting stickleback males. Next to one animation, water conditioned by a brother was added, while near the other, water from an unrelated male was added. In half of the experiments, the brother was familiar while in the other half he was unfamil-iar to the female. Both scenarios were carried out with both outbred and inbred Wsh. The results showed that the females adjusted their choice behaviour according to relatedness. Furthermore, they were able to recognise both familiar as well as unfamiliar brothers. Inbreeding did not aVect this ability. Hence, three-spined sticklebacks are able to recog-nise their relatives using olfactory cues alone. The cognitive mechanisms underlying this ability were independent from familiarity and not impaired by inbreeding