Regulation of ovarian diapause in Drosophila melanogaster by photoperiod and moderately low temperature

Abstract

Females of Drosophila melanogaster (Canton-S) enter an ovarian (adult) diapause under short photoperiods at moderately low temperature (< 14°C), whereas those exposed to long days become vitellogenic. The incidence of diapause in short days, and the value of the critical day length, are both very sensitive to slight rises in temperature. The photoperiodic response also varies between wild type strains, diapause incidence in Oregon-R being the lowest in the conditions tested. Sensitivity to the diapause promoting effect of short days and cool temperature commences soon after eclosion and is restricted to the adult stage. No difference in the propensity to enter diapause was observed between flies eclosing at different times in the “gate”, but newly eclosed flies must be transferred to diapause promoting conditions within about 10 h of eclosion. The comparatively “shallow” nature of the response in D. melanogaster probably reflects the relatively recent evolutionary origin of the diapause in this essentially commensal species.