Selective neuroanatomical plasticity and division of labour in the honeybee

THE mushroom bodies in the protocerebrum are believed to be the structures of the insect brain most closely associated with higher-order sensory integration and learning1. Drosophila melanogaster mutants with olfactory learning deficits have anatomically abnormal mushroom bodies or altered patterns of gene expression in mushroom body neurons2–4. In addition, anatomical reorganization of the mushroom bodies occurs in adult flies5, and possibly in adult honeybees6,7; disturbance of electrical activity in this region disrupts memory formation in honeybees8. Little is known, however, about the relationship of naturally occurring anatomical changes in the mushroom bodies to naturally occurring behavioural plasticity. We now report that age-based division of labour in adult worker honeybees (Apis mellifera) is associated with substantial changes in certain brain regions, notably the mushroom bodies. Moreover, these striking changes in brain structure are dependent, not on the age of the bee, but on its foraging experience, thus demonstrating a robust anatomical plasticity associated with complex behaviour in an adult insect.

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