PHOTOPERIODIC TERMINATION OF DIAPAUSE IN AN INSECT

Abstract

1. The European corn borer, Ostrinia nubilalis, has a faculative diapause in the last larval instar. Diapause induced in the laboratory by a short-day photoperiod is identical in its intensity to that occurring in the field. 2. Diapause development occurs at 30° C. under various photoperiodic conditions but is greatly accelerated by a long day. 3. Completion of diapause development does not require a period of chilling. 4. Diapause development is a process that removes a block to secretion of the activation hormone but does not include secretion or any of the morphogenic events that follow.