Cadmium is one of the most potent pollutants which enters the environment through natural and/or anthropological sources and into the living organisms though the food chain thus realizing its toxic effect at all levels of biological organization. This work examines the effects of cadmium on the fitness-related traits, broad-sense heritability, genetic and phenotypic correlations, phenotypic plasticity, cost of plasticity, on direction of selection force and on antioxidative defense system in gypsy moth during larval development, pupal development and the adult period. Gypsy moth (Lymantria dispar L.) is a polyphagous, invasive species which, due to its detrimental influence on forest ecosystems, is considered an organism of particular interest for researches of physiological and evolutionary-genetic responses which can influence population dynamics of this species.