Age-dependent Change in Effects of Chilling on Diapause Termination in the Brown-winged Green Bug, Plautia crossota stali Scott (Heteroptera : Pentatomidae)

The time required for oviposition and change in body colour from brown to green after a 30 day-chilling was examined in diapause adults of Plautia crossota stali Scott. When day 20 or 30 diapausing adults were exposed to low temperatures of 15℃ or 10℃, or kept at 20℃ under short day conditions (LD12 : 12h) for 30 days, then transferred to 20℃ and long day conditions (LD16 : 8 h), the pre-oviposition period after transfer was not significantly different among the three temperature regimes. When chilling was started from day 45, the pre-oviposition period in the regime exposed to 10℃ was significantly longer than that of the 15℃-regime. In the three temperature regimes with chilling starting from day 60, the lower the temperature to which bugs were exposed, the later first oviposition occurred. The later chilling was started, the faster bugs tended to turn from brown to green, and the lower the chilling temperature, the slower the change in colour. A positive correlation was detected between the pre-oviposition period and the time required for the body colour change to occur after the transfer to 20℃ and long day conditions.