| Abstract: | Studies in the laboratory and insectary showed at least two strains of pink bollworm, Pectinophora gossypiella (Sänders) exist north of the equator in the cotton growing areas of the Western Hemisphere, when measured in terms of diapause. Nondiapause was revealed to be a multigenic character, which was not sex-linked. Families of insects were obtained that averted diapause even when reared under strong diapause inducing stimuli. Photoperiod proved to be the primary stimulus for diapause induction or prevention (nondiapause). Life history records established the average duration of the life stages to be; 4.8, 16.4, 9.2 and 17.5 days for egg, larva, pupa and adult respectively when reared at 26.7°C and 9.8, 51.7, 24.4 and 37.days respectively when reared at 18.3°C. There were no significant difference among overall egg to egg life cycles of the various populations studied. |
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