Fig. 1. Right: Schematic insect, middle: Cross-section through its integument highlighting CHC transport pathways and their deposition on the epicuticle, left: examples of the three most commonly occurring CHC compound classes n-alkanes, n-alkenes, and methyl-branched alkanes.

CHC biosynthesis occurs in specialized secretory cells, the oenocytes, which are mainly embedded in clusters in the epidermis or dispersed within the fat body depending on insect species and developmental stage. After their biosynthesis, CHCs are shuttled through the hemolymph by the high-density lipoprotein lipophorin, with subsequent transport to the epicuticular surface via specialized pore canals penetrating the cuticular layers. Gray arrows indicate CHC transport pathways, drawings by Lukas Schrader.