none Enter Exposure of the diapause individuals to 27-29[degree]C and 1.5 mL/L n-hexane for 10-15 min can effectively terminate diapause in Cotesia vestalis (Haliday). To unravel the mechanism of diapause termination, hydrogen peroxide content and activities of three antioxidant enzymes, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were quantified in diapause prepupae of C. vestalis. Results showed that, in the n-hexane-exposed diapause individuals, hydrogen peroxide content and activities of SOD and POD increased sharply, while activity of CAT declined. On average, hydrogen peroxide content and SOD activity were significantly higher in the exposed diapause prepupae than those in unexposed both diapause and non-diapause prepupae; POD activity was significantly lower than that in non-diapause prepupae but significantly higher than that in unexposed diapause prepupae; CAT activity was significantly lower than that in the unexposed diapause prepupae but significantly higher than that in non-diapause prepupae. Hydrogen peroxide content depends on activities of the three antioxidant enzymes, while the fanner can regulate hormone level in diapause prepupae, which may be the reasons for diapause termination by n-hexane. noneEmail20150305 (houjiaxiu1988@163.com)