Objective Effects of low temperature on reactive oxygen and cold-tolerant protective enzymes activity of Ectropis grisescens Warren were studied.

Method Male and female E. grisescens adults were placed under -5, 0, 5, 10, 15, and 20℃, along with 25℃ as control, for an hour prior to measurements for H₂O₂ as well as activities of lactate dehydrogenase (LDH), glutathione reductase (GR), acid phosphatase (ACP), and alkaline phosphatase (ALP) in the insects. The two sets of data collected were statistically analyzed for correlation.

Result The H₂O₂ content in E. grisescens peaked under 5°C and decreased gradually below that temperature. The significantly higher activity of GR in the male than the female moths rose with increasing treatment temperature. No statistically significant disparity was found between the males and the females, but significantly lower in the female than the control moths, on the LDH activities under all tested temperatures. On the other hand, lower temperature suppressed ACP and significantly more so on the males than the females. For the activity of ALP, as the temperature was lowered from 10, 5, 0°C to -5°C, it increased gradually in the males and varied significantly by the treatments.

Conclusion Low temperature exposure significantly affected the H₂O₂ content and activities of cold-tolerant protective enzymes in adult E. grisescens. The effects varied significantly between the males and females.