Influence of Temperature on Diapause Termination in Ooencyrtus ennomus1, an Elm Spanworm2 Egg Parasitoid

Abstract

Chilling hastened diapause termination in Ooencyrtus ennomus Yoshimoto as measured by numbers of days to adult emergence at 24°C. Photoperiod had no detectable effect on diapause termination. The mean number of days for the adult parasitoid to emerge after chilling decreased as the duration of chilling increased. The mean number of days at 24°C for adults to emerge after 60 days of chilling was 63 as compared to 41 days after 150 days of chilling. Diapause was terminated in about 30 days by exposing unchilled larvae to 30°C. It was also terminated in unchilled larvae at 24°C, though adult emergence took 88.2 days.