summary
animals have endogenous clocks that regulate their and physiology. these clocks rely on environmental cues (time givers) that appear approximately every 24 h due to the earth’s rotation; thus, most insects exhibit a circadian rhythm. one notable exception is the scarab beetle, holotrichia parallela, a severe agricultural pest in china, japan, south korea, and india. females emerge from the soil every other night, reach the canopy of host plants, evert an abdominal gland, and release a pheromone bouquet comprising l-isoleucine (lime) and l-linalool. to determine whether this circa’bi’dian rhythm affects the olfactory system, we aimed to identify h. parallela receptor(s) and study their expression patterns. we cloned 14 (ors) and attempted de-orphanizing them in the recording system. hparor14 gave robust responses to lime and smaller responses to l-linalool. structural modeling, tissue expression profile, and treatment followed by physiological and behavioral studies support that hparor14 is a sex pheromone receptor—the first of its kind discovered in coleoptera. examination of the hparor14 transcript levels throughout the adult’s life showed that on sexually active days, gene expression was significantly higher in the than in the . additionally, the hparor14 expression profile showed a circabidian rhythm synchronized with the previously identified pattern of sex pheromone emission. 48 h of electroantennogram recordings showed that responses to lime were abolished on non-calling nights. in contrast, responses to the (z)-3-henexyl acetate remained almost constant throughout the recording period.
current biology，if=9.2
