Absence of within-colony kin discrimination behavioural interactions of swarm-founding wasps

Within-colony kin discrimination has not been demonstrated conclusively for any social insect, perhaps partly because highly polymorphic genetic markers necessary to assess within-colony relatednesses have only recently become available. We use microsatellite loci to investigate within-colony kin discrimination in behavioural interactions in the neotropical multiple-queen wasp, Parachartergus colobopterus. Within-colony kin discrimination would be particularly advantageous in this species since average genetic relatedness among colony members overall is low (0.32 ± 0.06), compared to the relatedness value between full sisters of 0.75. Using seven colonies of individually marked females, we recorded behavioural interactions that were cooperative (222 grooming, 2438 feeding), aggressive (511 body or wing biting, 240 mandible biting) or neutral (1676 antennating). We expected cooperative behaviours to favour closer kin and aggressive behaviours to be directed towards more distant kin, but found that none of the behaviours we investigated showed discrimination on the basis of relatedness. We could have detected a difference in relatedness values of as little as between 0.03 and 0.12, depending on the behaviour being analysed. Thus, we found no evidence for kin discrimination in within-colony behaviour in this species.