COMBINED EFFECTS OF PYRIPROXYFEN AND Bacillus thuringiensis ON ANTIOXIDANT ACTIVITY OF HEMOLYMPH, MIDGUT AND FAT BODY OF Galleria mellonella LARVAE

Insect growth regulators and microbial insecticides are mostly used in pest management since they are nontoxic to other organisms and have short half-life in the environment. Effects of juvenile hormone analogue pyriproxyfen and Bacillus thuringiensis on antioxidant enzyme (catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities of hemolymph, midgut and fat body of Galleria mellonella larvae was investigated. Larvae were exposed to LD50 values of pyriproxyfen and B. thuringiensis (LD50 of B. thuringiensis: 359 mg/L; LD50 of pyriproxyfen: 2385 mg/L), then enzyme activities were measured spectrophotometrically after 72 hours from treatment. When LD50 value of pyriproxyfen and B. thuringiensis were applied to G. mellonella larvae singly and in mixture, the activities of SOD, CAT and GPx were significantly increased in hemolymph and fat body of G. mellonella larvae, whereas the enzyme activities were significantly decreased in midgut of larvae compared with the control group. As a result of this study, we observed that pyriproxyfen and B. thuringiensis effect the antioxidant defence system of G. mellonella larvae even if at low doses. If this kind of insecticides were applied at sublethal doses, economical, biological and ecological benefits were achieved as well.