Abstract: 【Aim】 This study aims to determine the effects of temperature on the activities of key enzymes related to respiratory metabolism in adults of the bean bug, Riptortus pedestris. 【Methods】 The activities of five key enzymes related to respiratory metabolism, i.e., glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerol-3-phosphate (GDH), 3-hydroxyacyl-CoA dehydrogenase (HOAD), citrate synthase (CS), and lactate dehydrogenase (LDH), in R. pedestris adults exposed to different temperatures (16, 20, 24, 28, 32 and 36℃) for 4 h in scotophase were assayed by using biochemical methods. 【Results】 The results showed that the activities of the five key enzymes in R.pedestris adults increased first and then decreased as the temperature increased. The CS activities at 16 and 28℃ differed significantly between males and females, being higher in females than in males at 16℃, but lower in females than in males at 28℃. The LDH activities in males were higher than those in females at 36℃, suggesting that there are significant differences between males and females in the tricarboxylic acid cycle metabolism at low temperature and in the anaerobic glycolysis at high temperature. The ratios of GAPDH activity to HOAD activity in adult males and females exposed to different temperatures were much higher than 1.0, indicating that R. pedestri adults mainly consume carbohydrates in respiratory metabolism at the test temperatures. 【Conclusion】 In the temperature range from 16℃ to 36℃, with the increase of temperature, the activities of key enzymes involved in respiratory metabolism in female and male adults of R. pedestris increase at first, and then decrease. R. pedestris can adjust its respiratory metabolic intensity to some extent to adapt to temperature change.

Key words: Riptortus pedestris, temperature, respiratory metabolism, enzyme activity, energy substance