H6PD and infection: Antioxidant activity was assessed by measuring GP and GR in the midgut and G6PDH in the head in Experiment A, and by measuring SOD, CAT, and GST in the head and G6PDH in the abdomen in Experiment B. Modifications in antioxidant activity occurred exclusively in Experiment B. Infection altered SOD, CAT, and G6PDH, irradiated affected G6PDH, and combined exposure influenced CAT, G6PDH, SOD, and GST.