HOUR-GLASS DUSK AND RHYTHMIC DAWN TIMERS CONTROL DIAPAUSE IN CODLING MOTH

In the codling moth, Carpocapsa pomonella, of 72 hr, with 8-hr photophases and interrupted nights, produce significant depressions of the diapause curve 8 hr after dusk and 8 hr before dawn. These maxima for diapause inhibition are phase-locked to dusk and dawn. The dusk inhibition curve tends to be linear with time up to 8 hr after dusk, does not reset, and thus has typical 'hour-glass' characteristics. The dawn timer is rhythmic, with an approximately 24-hr period. On photocycles shorter than 72 hr, the two timers interact with each other significantly. © 1969.