Influence of Light on Diapause in the Boll Weevil I. Dependence of Diapause Response on the Spectral Composition of the Light Used to Extend the Photoperiod123

Abstract

Regions of the near-ultraviolet and visible spectrum effective for inducing diapause suppression in the boll weevil, Anthonomus grandis Boheman, were investigated. One group of weevils was exposed to 11 hours of fluorescent light-time and 13 hours of dark-time that initiated diapause (L11:D13); the 2nd group was exposed to 13 hours of fluorescent light-time and 11 hours of dark-time that inhibited diapause (L13:D11). A 3rd group was exposed to 11 hours of fluorescent light-time followed by 2 hours of illumination with narrow wavebands of light of different spectral compositions and 11 hours of dark-time (L11+2:D11). The spectral region most effective for suppressing diapause was found to be between 400-665 nm. The 359-390 nm and 670-1000 nm spectral regions were less effective.