Larvae of the bamboo borer, Omphisa fuscidentalis, enter larval diapause in September and pupate in the following June (Singtripop et al., 1999). We examined the changes in the responses of larvae to exogenous 20-hydroxyecdysone (20E) in order to estimate the progress of diapause development. In this respect, we adopted two terms, responsiveness and sensitivity of larvae to 20E. Responsiveness ...