Effects of Environmental Factors on Diapause Development and Postdiapause Oviposition in a Phytophagous Insect, Dybowskyia reticulata

Abstract

Abstract Environmental factors that regulate the induction, maintenance and termination of adult diapause and postdiapause oviposition were examined in a phytophagous insect, Dybowskyia reticulata (Heteroptera: Pentatomidae). When insects were reared from eggs at 25°C in the laboratory, all adults under a short-day photoperiod of 12:12 (L:D) hr and most adults under a long-day photoperiod of 16:8 (L:D) hr entered diapause. Overwintering adults started oviposition after being transferred to the long-day or short-day photoperiod at 25°C in March. Under the short-day photoperiod, however, they entered diapause again after a short oviposition period. Transferral to a long-day photoperiod after a long exposure to a short-day photoperiod synchronously terminated diapause. After exposure to a low temperature during diapause, the adults began to lay eggs under both long-day and short-day photoperiods. Low temperature in winter probably plays a dominant role in the termination of diapause in nature. In addition, t...