Abstract
Diapause development in the bollworm, Heliothis zea (Boddie), and the tobacco bud worm, H. virescens (F.), was compared in central Texas during 1980–1981 by collecting overwintering pupae from a field of pigeon peas, Cajanus cajun L., throughout the overwintering period and determining their diapause condition and the number of days to adult emergence at different temperatures. The pattern of diapause development in central Texas is similar in both species and apparently consists of two distinct developmental phases. Phase one occurs at low temperatures during the fall and early winter and leads to the attainment of a physiological state beyond which the overwintering pupae will not develop under the prevailing low temperature conditions. Phase two occurs at higher temperatures and leads to diapause termination. That H. zea overwintering pupae in phase two development consistently required significantly longer exposures to the study temperatures for diapause termination and for adult emergence, explains why H. virescens has been reported to emerge from overwintering before H. zea . Males of both species also required significantly longer exposures than the females. The temperature threshold for reactivation leading to diapause termination is apparently similar for both species.
Published Version
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