Effect of Cadmium Dietary Intake on Midgut Β-Glucosidase of Lymantria Dispar Larvae

A crucial enzyme in feeding and survival of Lymantria dispar (gypsy moth) caterpillarsis β-glucosidase. Considering that this herbivorous species is oneof the most damaging pests, a study of the enzyme that hydrolyzesplant polysaccharides is of invaluable significance. The knowledgeof glucosidase alterations helps clarify our understanding of theinsect pest feeding strategy in highly polluted environments. Wesought to find out whether acute and chronic exposures to cadmium(10 and 30 mg Cd/g dry food), as well as the recovery from long-termtreatment, influence the specific activity of midgut β-glucosidase.Cadmium ingestion did not alter enzyme activity compared to control,regardless of the treatment duration and metal concentration. Theonly statistically significant increase in enzyme activity was detectedduring the recovery after chronic treatment at 10 mg Cd/g dry foodcompared to the chronic cadmium effect at the same metal concentration. Duringchronic treatment at a lower cadmium concentration (10 mg Cd/g dryfood), the phenotypic plasticity index was higher than at the recoveryfrom the same concentration, while the variability of plasticityamong these treatments was higher after recovery. Only one enzymeisoform was detected, which indicates its ability to hydrolyze severalsubstrates. We concluded that this enzyme is probably essentialfor larval nutrition and survival in the presence of high amountsof cadmium in the food.