Phytophage–entomophage interactions at different stages of mass reproduction of forest insects

Abstract

A model that implies highly inertial regulation of phytophage numbers by entomophages has been applied for the analysis of phytophage–entomophage interactions during different phases of the gradation cycle of phyllophagous insects. The data on population dynamics and the degree of parasite infestation in pupae of the pine looper Bupalus piniarius L. and fir looper Ectropis (=Boarmia) bistortata Gz are used to verify the model. The results of field studies apparently are in good agreement with the model of highly inertial regulation in the “phytophage–entomophage” system. The model that is proposed explains the decisive roles of different factors (entomophages, predators, or diseases) in the population dynamics of phytophages under different conditions.