Kin recognition in Aleochara bilineata could support the kinship theory of genomic imprinting.

Genomic imprinting corresponds to the differential expression of a gene according to its paternal or maternal origin. The kinship theory of genomic imprinting proposes that maternally or paternally inherited genes may be in conflict over their effects on kin differently related along the paternal or maternal line. Most examples supporting the kinship theory of imprinting deal with competition between offspring for maternal resources. However, genomic imprinting may also explain differential behavioral expression toward kin whenever sibs are more related to each other via one parental sex than the other. Unfortunately, nothing is currently known about imprinting associated with a behavioral phenotype in insects. Here we report the first evidence of such a maternally imprinted behavior. We show that the solitary parasitoid larvae of Aleochara bilineata Gyll (Coleoptera; Staphylinidae), which avoid superparasitizing their full sibs, also avoid their cousins when they are related to them through their father, but not when they are related to them through their mother. A genetic kin recognition mechanism is proposed to explain this result and we conclude that genomic imprinting could control the avoidance of kin superparasitism in this species and have a profound influence on decision-making processes.