Induction and termination of pupal diapause in relation to the change of ecdysone titer in the fleshfly, sarcophaga peregrina

Abstract

Larvae of Sarcophaga peregrina entered pupal diapause under a certain short day condition through embryonic stage to mature larvae. The critical day length for 50% induction of pupal diapause was 13 L: 11D cycles at 22C, but the effect of the short day was enfeebled by higher temperature. In order to break the diapause, pupae had to be exposed to low temperature for 8 weeks or more, though spontaneous termination of diapause occurred by placing the pupae for a longer term at 25C. Eddysone contents of the whole body varied with their developmental stage from the mature larvae to pupae. In both diapause and nondiapause pupa, the ecdysone titer began to increase after transferred to dry condition and reached a maximum 12 hr after pupariation. About 40 hr after pupariation, the ecdysone titer decreased to minimum values. Afterwards, only in non-diapause pupae, the titer began to increase again at the time of larval-pupal ecdysis. The second peak of ecdysone titer is thought to be responsible for adult development, since the peak was not seen in diapause pupae. © 1972, National Institute of Infectious Diseases, Japanese Journal of Infectious Diseases Editorial Committee. All rights reserved.