Group relatedness and kin discrimination in honey bees Apis

Äbstract. In addressing problems concerning kin discrimination and the evolutionary significance of inclusive litness in highly eusocial insects, the genetic relatedness between groups, such as individuals belonging to the same patriline within colonies, is of interest. Based on the definitions for individual genetic relationship, several new measurements of group relatedness are derivcd and their genetical meaning is discussed. In a metabolic bioassay for the documentation of kin discrimination, carbon dioxide production was used to quantily reactions of groups of honey bees to volatile odours of other groups. Worker test groups, which had not experienced their hive environment, were able to discriminate between related and unrelated groups of workers within and between colonies. Test groups responded in a similar way to odours ofgenotypically mixed groups with related and unrelated workers and to the odours ofpure groups ofthe less related subgroup. Thus, the reaction to group odours that function as discrimination labels is not a lincar response as predicted by an additive gestalt odour model. Since experienced bees collected from the colony could not discriminate between the various patrilines, the observed phenomenon resembles nest mate recognition rather than within-colony kin recognition. Though kin selection theory is a highly plausible model for the evolution of sociality (Hamilto