Intraspecific nest and brood recognition by queens of the bumble bee, Bombus occidentalis (Hymenoptera: Apidae)

Queens of pre-emergence colonies of the bumble bee, Bombus occidentalis, discriminated between their own nest or brood and that of an unrelated conspecific queen in the field. In particular, behavioural observations of queens from 11 matched pairs of replaced nests (controls) and switched nests (treatments) revealed that queens spent significantly more time in thermoregulatory behaviour (incubating and covering brood), and initiated such behaviours significantly sooner, with their own brood than with unrelated (foreign) brood. Queens also spent significantly more time inspecting foreign brood than their own brood. Finally, queens returning to foreign nests were significantly more likely to depart during the observation period than queens returning to their own nest. Although queens recognized unrelated nests or brood, they were not observed to destroy unrelated brood. Rather, in most cases they adopted foreign nests containing unrelated worker-destined brood, and remained with these nests for the life of the colonies.