Age-mediated and environmentally mediated brain and behavior plasticity in the stingless bee Melipona quadrifasciata anthidioides

Abstract

Structural changes in the insect brain related to age and individual experience may underlie the behavioral plasticity that is particularly important in such social insects as bees. This study assessed the influence of age and rearing conditions (field vs laboratory) in mediating changes in the volume of mushroom bodies and antennal lobes in the brains of workers of the native stingless bee Melipona quadrifasciata anthidioides Lepeletier, a pollinator species with small colonies exhibiting high level of sociability and behavioral versatility. Although only age-dependent enlargement was observed in the antennal lobes, significant increase (21 %) in the neuropils of the mushroom bodies occurred before the foraging age, in contrast to honeybees, and environmental complexity led to a significant increase in both the mushroom body volume and the walking activity. Such differences in the stingless bee M. quadrifasciata anthidioides as compared with the honeybee may assist in relating brain evolution and plasticity with the behavior in these social insects.