Brain differences among the physical castes of Nasutitermes corniger (Blattodea: Termitidae)

Division of labor among social insects has been the hallmark of advanced social evolution. Although morphological and/or physical castes (difference between reproductive and workers) are ubiquitous, only a small percentage of the social hymenoptera exhibit morphological specialization among the worker caste. However, within termites, physical polymorphism within the worker castes is the rule, rather than the exception; with most termite species having a morphologically distinct soldier caste. Although the physical differences between the castes, both reproductives and workers have been well studied, little is known about the brain differences among these groups. Here we used Nasutitermes corniger to investigate differences among termite castes. We examined how reproductives’ brains change from colony founding to established colonies and the differences between termite workers and soldiers. We found that the sensory neuropil of reproductives reduces with colony age in both sexes  and that soldiers had a distinct brain morphology that was different than workers. We will discuss the implications of how brain differences among the physical castes could be under selection.