Effects of period RNAi on V-ATPase expression and rhythmic pH changes in the vas deferens of Spodoptera littoralis (Lepidoptera: Noctuidae)

► Epithelium of the upper vas deferens (UVD) contains an oscillator with PERIOD protein (PER) as the key regulatory component. ► Rhythmical expression of period gene can be transiently reduced in cultured male reproductive organs using the RNAi method. ► Expression of V-ATPase subunits c in the UVD epithelium is rhythmic and directly dependent on the PER protein. ► PER-based oscillator in the UVD epithelium drives rhythmic pH changes by affecting V-ATPase expression.