The Sensitivity of Dendrolimus spp.to Light Intensity and Spectrum in Photoperiodic Reaction

The results demonstrate that pine caterpillars are quite sensitive to the illumination of fluorescent lamp and they even can perceive the light in intensity below 0.1 lx.However,these pests show sheer opposite responses to the light spectrum below or above 570 nm,they lost the physiological response to the light above 570 nm.Consequently,the twilight can be neglected in calculating thenatural photoperiods,because twilight does not contain the light below 570 nm,even though its illumination can reach 300 lx.The influence of photoperiodic reaction of pine caterpillar on its population dynamics is also discussed considering the effects of forest on sun light through the canopy's reflection and absorption.