COMPARISON BETWEEN THE VARIATION OF DETOXIFYING CAPACITY AND THE DIFFERENT SUSCEPTIBILITY TO MALATHION ACCORDING TO THE AGE OF NYMPHS-V OF TRIATOMA-INFESTANS

The tolerance to the organophosphorus insecticide malathion in nimphs V of Triatoma infestans was notabily higher at the end of this larval stage. The possibility of this differential toxicity response dependent on nimphs V age were due to changes in the detoxifying capacity mediated by hydrolases or glutathione transferases. The experimental evidences obtained would indicated that the malathion carboxyesterases would not be the primary cause of the differential toxicity but the glutathione transferases and phosphorotriesterases could contribute to explain this phenomenon.