Synopsis : The science of identity … how guard bees recognise nestmates, why drifting bees are accepted into other hives and why robbers are only sometimes rejected.
Honey bees are eusocial insects. The ’eu’ before social is derived from the Greek for ‘good’; these insects – not just honey bees – exhibit the highest level of social organisation, involving the division of labour (nurses, scouts, guards, foragers and in reproductive and non-reproductive sub-groups), cooperative brood rearing and overlapping generations.
Eusociality is a response to evolutionary pressure. Colonies are more successful than individuals.
Sociality involves cooperation. This requires recognition of kin and/or other group members. It also involves defending the shared resources that the group have worked together to collect (stores) or rear (brood).
Without defence, all that hard work would be lost to other competing groups who would try and steal the resources.
Social groups have therefore developed ways to distinguish themselves from other social groups of the same species. Although some social insects use visual clues 1 to distinguish group members (Baracchi et al., 2015), the majority use odours, in particular cuticular hydrocarbons (CHC’s).