Abstract: 【Aim】 This study aims to clarify the effects of temperature on the activities of key enzymes related to respiratory metabolism in adults of the Siberian grasshopper, Gomphocerus sibiricus. 【Methods】 By using biochemical methods, the activities of five enzymes, i.e, glyceraldehyde-phosphate (GAPDH), glycerol-3-phosphate (GPDH), lactate dehydrogenase (LDH), 3-hydroxyacyl-CoA dehydrogenase (HOAD) and citrate synthase (CS), in G. sibiricus adults were measured after they were treated in Light Emitting Feed Box for 4 h under darkness within a temperature gradient of 18-42℃ in a 3℃ interval. 【Results】 The activities of five key enzymes related to respiratory metabolism in G. sibiricus adults increased firstly and then decreased, with the values of males higher than those of females at the same temperature. The enzyme activities in both males and females were the minimum at 18℃. The activities of GAPDH and CS of females reached the maximum at 39℃, while the CS activity in males reached the peak at 36℃. At different temperatures, the enzyme activities between males and females were significantly different (P<0.05) except the CS activity, and the ratios of GAPDH activity to HOAD activity were more than or close to 1.0, suggesting that carbohydrates are consumed for respiration at lower temperature, while lipid and carbohydrates are used as energy substances at higher temperature. 【Conclusion】 Temperature has significant effects on the activities of key enzymes related to respiratory metabolism in G. sibiricus adults, which change the intensity of respiratory metabolism and energy substrates for improving the capacity of adapting to high temperature stress.

Key words: Gomphocerus sibiricus; respiratory metabolism, temperature stress, energy substance, enzyme activity