RNA interference is a powerful tool for chronobiological study in the cricket

Circadian rhythms are periodic phenomena recurring with a period of about 24 h that are observed in a variety of physiological functions. The rhythms are driven by an endogenous timing system involving the circadian clock. While recent molecular studies promoted understanding the oscillatory mechanism of the clock in model organisms such as Drosophila, its applicability to other insects still remains to be examined. RNA interference (RNAi) becomes a powerful method to dissect the clock and clock-related mechanisms in non-model insects. Crickets are particularly suitable for the application of RNAi, because a single injection of a clock gene dsRNA has long-lasting effects both on mRNA and behavioral rhythms. In this review, we introduce our current approach to the circadian clock as well as photoperiodic time-measurement mechanism in crickets, and describe the effectiveness of nymphal, adult, and parental RNAi in studies of biological timing mechanisms.