Olfactory cues and Vespula wasp recognition by honey bee guards

Guard honey bees patrol the entrance to the nest and are thought to recognise nestmates by cuticular hydrocarbons. We aimed to determine whether honey bee guards can recognise predatory common wasps Vespula vulgaris and nestmates by olfactory cues. Odours were transferred between both honey bees and wasps and the responses of guards to controlled introductions monitored. When controlling for the species of introduced insect, the transferred odour was a predictor of aggressive attacks on both bees and wasps. Carriers of incongruous, allospecific odours were antennated by more guards than carriers of conspecific odours. Olfactory cues were, therefore, transferred and guards responded not only to odour per se but also odour incongruity. Olfactory cues may therefore be important in predator recognition by honey bee guards.