Kin Recognition and Inbreeding Avoidance in a Butterfly

Owing to the risk of inbreeding depression, the evolution of inbreeding avoidance by means of kin recognition is expected for many biological systems. Nevertheless, an ability to distinguish among relatives and non-relatives has been only rarely demonstrated, especially so in non-social organisms. We here show that, in the non-social tropical butterfly Bicyclus anynana, females discriminate against relatives by preferentially mating with non-relatives. Inbreeding avoidance was more pronounced in inbred as compared with outbred butterflies, suggesting that it is partly condition dependent. We argue that, in our system, the evolution of inbreeding avoidance is related to carrying a high genetic load and thus to being particularly sensitive to inbreeding depression. We suggest that kin recognition might be more widespread than currently thought and that future studies may possibly benefit from considering condition dependence, especially by paying attention to and/or manipulating population history, genetic load, and the risk of inbreeding depression. We further suggest that kin recognition in B. anynana might be based on cuticular hydrocarbons used for self-referencing.