Sensitive stages for photoperiodic induction of pupal diapause in the flesh fly Sarcophaga similis (Meade) (Diptera: Sarcophagidae)

Photoperiod is a major factor in the induction of pupal diapause in the ovoviviparaous flesh fly, Sarcophaga similis. This species entered diapause when kept under short-day conditions throughout the embryonic and larval stages. Exposure to long-day conditions for the whole embryonic or whole larval stage, however, prevented diapause. Moreover, most insects did not enter diapause when they were exposed to long-day conditions for only 2 days in the embryonic stage just before larviposition. When the uterus containing embryos was removed from the mother's body and kept in vitro under long-day conditions, most of these embryos became nondiapause pupae even under subsequent short-day conditions. When postfeeding larvae were exposed to long-day conditions for 3 days, 50% entered diapause. From these results, it is concluded that sensitivity to photoperiod is highest in the later embryonic stage and embryonic sensitivity to photoperiod is independent of the mother.