Neuroanatomical Dissection of the Honey Bee Brain Based on Temporal and Regional Gene Expression Patterns

Abstract

To identify the molecular and neural bases of honey bee social behavior and dance communication, we performed a neuroanatomical dissection of the honey bee brain based on molecular techniques. We systemically searched for genes, peptides, and proteins that are expressed in a region-preferential manner or whose expression differs depending on the behavior of an individual honey bee. Large- and small-type Kenyon cells (KCs) that comprise the honey bee mushroom bodies (MBs) have distinct gene expression patterns. Based on their temporal and regional expression profiles, the large- and small-type KCs are assumed to play a major part in calcium-signaling-mediated learning and memory, and ecdysteroid-signaling-mediated division of labor of workers, respectively. In addition, analysis of the neural activity in forager brains using a novel immediate early gene indicated that the small-type KCs are active in forager brains, suggesting that the small-type KCs are involved in processing information during the foraging flight. Furthermore, we identified two genes expressed preferentially in the monopolar cells of the optic lobes (OLs), the visual center in insect brains, and a novel gene expressed preferentially in a neural subpopulation located in the anterior to posterior dorsal OL region. Based on these findings, we propose that advanced ‘module-functionalization’ based on differential gene expression patterns could be a prominent feature of the honey bee brain.