Photoperiod Control of an ‘Obligatory’ Pupal Diapause

Abstract

AbstractEvidence is provided that an obligatory pupal diapause is controlled by photoperiod. Diapause in H. cecropia is induced and maintained by a 12-hour photoperiod, and prevented or terminated by a 17-hour photoperiod; in either case, the incidence of diapause is graded according to the developmental stage at which the light regime is imposed. The validity of the distinction between "facultative" and "obligatory" diapause is discussed in the light of these results.