Morphological, physiological, and trophic characteristics of the gypsy moth Lymantria dispar L. (Lepidoptera, Lymantriidae) larvae in relation to the hydrothermal conditions and the population density

Analysis of changes of morphometric and trophic characteristics depending on the rainfall and temperature was performed in two populations of the gypsy moth larvae during depression and outbreak. The data obtained were analyzed from points of view of existing hypotheses concerning the reasons of outbreaks. The narrowing of the norm of reaction of a population before outbreak explains the data obtained.