Effects of photoperiod and temperature on termination of summer diapause in pupae of Antheraea yamamai

Abstract

Effects of various photoperiods and temperatures on termination of summer diapause were examined in Antheraea yamamai pupae. When the newly ecdysed pupae were kept under short-day photoperiods of 8L-16D to 12L-12L at 25°C, pupal duration till emergence was shortened greatly and range of moth emergence was narrow. On the contrary, when they were kept under long-day photoperiod of 16L-8D, the pupal duration was much prolonged and the emergence range became wider. When exposed to a photoperiod of 14L-10D, the pupal duration and the emergence range were intermediate. From these, it is obvious that termination of pupal summer diapuse in this species is accelerated by short-day photoperiod and retarded by longday photoperiod. Subsequently, the pupae were exposed to 15°C, 20°C, 25°C, or 30°C at 12L-12D till emergence. The lower the temperature given, the longer the pupal duration but the narrower the range of moth emergence. Thus, it is suggested that relatively low temperature will be also effective for the termination of pupal summer diapause.