Abstract: 【Aim】 The wireworm Melanotus caudex occurred more and more severely in recent years. To reveal the physiological and ecological adaptations of M. caudex larvae under starvation stress, their physiological changes under starvation stress were assayed. 【Methods】 Using 2-3 instar larvae as the initial test objects, we determined the survival, mobility, molting times, body weight, water content and respiration rate of M. caudex larvae bred on soil and vermiculite as culture substrates under starvation stress compared with those fed on wheat seedlings (Zhonghan 101 strain) on both substrates as the controls. 【Results】 There was no significant difference in the survival rate and molting times of M. caudex larvae between the starvation stress groups and the control groups. When M. caudex larvae were starved for 120 d, their survival rate was still over 90% and molted about 10 times. Both the wet and dry weight of M. caudex larvae under starvation in soil and vermiculite significantly decreased as compared with the controls, while the water content of the larvae under starvation in the soil and vermiculite environment(72.52% and 72.22%, respectively) increased significantly as compared with the corresponding controls (49.01% and 51.37%, respectively). The CO₂ release rates of the starvation stress groups decreased dramatically in the soil and vermiculite environment as compared with the controls, reducing by 62.11% and 60.46%, respectively. 【Conclusion】 M. caudex is an insect highly tolerant to starvation. The larvae can sustain their development (e.g., normal molting) by reducing respiratory metabolism during lack of food supply.    

Key words: Melanotus caudex, starvation, physiological characteristics, respiration rate, quiescence