Our previous study identified a DGAT gene which regulates the biosynthesis of bombykol precursor, TAG9. The present study went further to demonstrate the role of GPAT, an upstream component of DGAT, in bombykol biosynthesis. Combined both findings, we conclude that bombykol precursor are synthesized and stored in the cytoplasm in the form of TAGs via the GAP pathway. Once stimulated by PBAN, the corresponding lipases promote TAG lipolysis and release the bombykol precursors for final sex pheromone biosynthesis (Fig. 7). In animals GPAT1 is regulated by sterol regulatory element-binding protein-l, insulin signal, etc. BmGPAT has been proved to be an important component for sex pheromone precursor biosynthesis. However the corresponding regulatory mechanism of BmGPAT in PGs remains elusive and requires further studies.