Abstract

Recent evidence suggests that asymmetry between the left and right sides of the brain is not limited to
vertebrates but extends to invertebrates as well. We compared olfactory lateralization in two species of
Hymenoptera Apoidea, the honeybee (Apis mellifera), a social species, and the mason bee (Osmia cornuta),
a solitary species. Recall of the olfactory memory 1 h after training to associate an odour with a sugar
reward, as revealed by the bee extending its proboscis when presented with the trained odour, was better
in honeybees trained with their right than with their left antenna. No such asymmetry was observed in
mason bees. Similarly, electroantennographic responses to a floral volatile compound and to an alarm
pheromone component were higher in the right than in the left antenna in honeybees but not in mason
bees. These findings seem to support recent game–theoretical models suggesting that population-level
lateralization is more likely to have evolved in social than in non-social species.