Sex pheromone production for most moths is regulated by pheromone biosynthesis activating neuropeptide (PBAN). In Bombyx mori, PBAN binding triggers the opening of store-operated Ca2+ channels, suggesting the involvement of a receptor-activated phospholipase C (PLC). In this study, we found that PLC inhibitors U73122 and compound 48/80 reduced sex pheromone production and that intracellular levels of 3H-inositol phosphate species increased following PBAN stimulation. In addition, we amplified cDNAs from pheromone glands corresponding to PLCβ1, PLCβ4, PLCγ and two G protein α subunits, Go and Gq. In vivo RNA interference-mediated knockdown analyses revealed that BmPLCβ1, BmGq1, and unexpectedly, BmPLCγ, are part of the PBAN signal transduction cascade.