Expression of elongase- and desaturase-encoding genes shapes the cuticular hydrocarbon profiles of honey bees

Most terrestrial insects have a layer of cuticular hydrocarbons (CHCs) protecting them from desiccation and mediating chemical communication. CHC composition is regulated by the expression of genes coding for enzymes in the biosynthetic pathway of hydrocarbons. The diversity and expression of these enzymes determine the abundance and richness of compounds in the CHC profile of an insect. For example, elongases are enzymes that lengthen the hydrocarbon chain, while desaturases introduce double bonds in it. CHC profiles of honey bees (Apis mellifera) vary among castes, task groups, and subspecies. This makes A. mellifera an excellent model to study the molecular mechanism underlying CHC biosynthesis. Here, we examined the expression of specific elongase- and desaturase-encoding genes and correlated gene expression with CHC composition in bees from two different task groups of two highly divergent A. mellifera subspecies: A. m. carnica and A. m. iberiensis. We show that in A. mellifera, the specificity of desaturases and elongases shapes the CHC profiles of different task groups. Our results shed light on the genetic basis for the task-specific CHC composition differences in social hymenopterans and lay the ground for further studies aiming to unravel the genetic underpinning of CHC biosynthesis. Moreover, these results underline the importance of investigating different subspecies of A. mellifera to better understand the mechanisms driving CHC composition.