Cellular and molecular aspects of adult brain development in honeybee castes (Apis mellifera L.)

Background The adult honey bee brain exhibits a complex architecture composed by millions of neurons, glial cells and their respective tracts which form structures known as neuropils. They are organized to produce the optic lobe, antennal lobe, central complex and mushroom bodies. Learning and memory-related skills that honeybee workers use for navigation, foraging, nestmate recognition, and other activities are believed to be associated with the mushroom bodies, which are more developed in the adult members of the worker caste. During larval period, however, the differential feeding offered to prospective queens promotes faster brain development and higher expression of several neurogenic genes (ataxin-2, cryptocephal, dachshund, Eph Receptor, fax, shot, kruppel homolog-1 and tetraspanin 5D) [1]. It seems that in some point during pupation, there happens a shift in this trend. In fact, queen’s brain experiences extensive cell death events, but worker’s brain is favored by higher rates of cell proliferation, resulting in caste specific brains [2].