Photoperiodic determination of insect development and diapause

Summary The Dual System Theory of photoperiodic time measurement is shown to provide a satisfactory basis for the interpretation of: (1) photoperiodic determination of diapause; (2) effects of different photoperiodic regimes on circadian rhythms of adult eclosion; and (3) the phase response curve. A fundamental unity of photoperiodic time measurement in a wide variety of organisms is strongly suggested by the Dual System Theory.Research supported by the College of Agricultural and Life Sciences of the University of Wisconsin, and by a research grant (GM 07557) from the National Institutes of Health