EFFECTS OF ELEVATION ON THE RATE OF DEVELOPMENT OF WESTERN SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) IN BRITISH COLUMBIA

Abstract

A simple empirical model of temperature variation with elevation was successfully used to explain variation in observed rates of development of larvae and pupae of the western spruce budworm in mountainous terrain. Hopkins' Bioclimatic Law did not adequately describe development of stages earlier than the sixth instar. Regional differences in the effect of elevation are demonstrated and related to coastal and interior conditions. Direct solar heating effects appear to be of major significance in the early instars. The empirically-derived rates of temperature decrease could be generally applied to regions with dry inland conditions, but not to moist coastal regions.