Bombykol is the first sex pheromone discovered and identified from the PGs of the silkworm moth Bombyx mori, located between the eighth and ninth segments of the ovipositor tip of females, which produce and release bombykol, (E, Z)-10, 12-hexadecadien-1-ol, as a major component of sex pheromones upon adult emergence6. Similar to other moths, B. mori synthesizes and releases bombykol under the regulation of PBAN. The actions of PBAN in B. mori have been well investigated and a series of associated genes involved in this process have been identified and characterized in detail5. Bombykol is synthesized in PG cells from acetyl-CoA via the fatty acid biosynthesis pathway. The biosynthetic fatty acid is converted into bombykol via the action of PG-specific desaturase 1 (pgdesat1) and PG-specific fatty-acyl reductase. Knockdown of the genes encoding pgdesat1 and PG-specific fatty-acyl reductase reduces bombykol production. This finding indicates that these two genes serve important functions in bombykol biosynthesis78. Before adult emergence, PG cells rapidly produce numerous bombykol precursors, lipid droplets (LDs) in the form of triacylglycerols (TAGs) stored in cytoplasm. A diacylglycerol acyltransferase 2 gene encoding for a speed-limiting enzyme of TAG biosynthesis was previously identified in B. mori PGs. RNAi knockdown of this gene significantly decreases bombykol production, suggesting that diacylglycerol acyltransferase 2 plays an important role in storage of TAGs, bombykol precursors9. After adult emergence, PBAN stimulates the lipolysis and subsequent reduction of LD TAGs to generate final bombykol10. Our previous study confirmed the high expression of seven lipase genes in PG cells through digital gene expression profiling. RNAi knockdown of four of the seven lipase genes individually leads to reduced bombykol production, suggesting that these four lipase genes are involved in the lipolysis process of TAGs1112. A similar function of PBAN induced movement of the stored pheromone precursor fatty acids in B. mori is also found in Manduca sexta13.