Biochemistry of insect learning: lessons from bees and flies

Recent advances in the study of learning in insects are examined with an emphasis on two of the most powerful model systems, the honeybee (Apis mellifera) and the fruit fly (Drosophila melanogaster). The honeybee exhibits easily manipulated feeding behavior coupled with extremely high mnemonic fidelity. The size of the honeybee brain has allowed for electrophysiological analysis of the neural correlates of behavior, sometimes with single cell resolution, as well as identification of critical brain regions. Drosophila has proved to be invaluable in the genetic dissection of learning. Through analysis of learning and memory mutants the biochemistry of critical steps has been elucidated and the temporal phases of memory in the fly have been described. Two regions of brain neurophil are essential for olfactory learning in these species: the antennal lobes and the mushroom bodies. In spite of similarities, temporal, and possibly biochemical aspects of learning differ markedly between these organisms.