Development and experience lead to increased volume of subcompartments of the honeybee mushroom body

The mushroom bodies of insects are believed to be involved in higher order sensory integration and learning. In the honeybee, the mushroom body can be separated into three different, modality-specific input compartments and several morphologically inseparable output regions. By means of morphometric analysis we show that the volumes of these subcompartments depend on both the age of the adult bee and its experience. For the most part a significant, age-dependent increase in neuropile volume is observed. Additionally, the olfactory and visual input regions show experience-related differences. Unlike other subcompartments, the visual input region does not change in volume with age, but only with experience. We thus suggest that experience is an important factor in the structural development of higher order brain regions of an insect, the honeybee.