The Endogenous Metabolic Response of Tribolium castaneum under a High Concentration of CO2

High carbon dioxide concentrations can effectively control most storage pests. To estimate the toxicity effect of high concentrations of CO2, four different concentrations of CO2 (25% CO2, 50% CO2, 75% CO2, and 95% CO2) were used to treat Tribolium castaneum, and the biochemical (carbohydrate content and gene expression level) and physiological (mortality, pupation, eclosion rate, and weight) features of insects submitted to different treatments with CO2 were evaluated. The T. castaneum mortality rate was 50% in approximately 2 days when exposed to a treatment with 95% CO2. When the CO2 concentration exceeded 75%, the pupation rate and eclosion rate of T. castaneum seriously declined. Higher than 25% CO2 concentrations resulted in a lower weight and shrunken body size of T. castaneum. It was further found that different CO2 concentration treatments all influenced the levels of the three carbohydrate contents in T. castaneum. In addition, according to the detection of trehalose metabolism pathway-related genes, T. castaneum mainly responds to stress factors via high expression of TPS, TRE1-2, and TRE1-3. Our results enrich the evaluation of the toxicity effect of CO2 treatment on grain storage pests, providing a basis for further improving the method of regulating grain storage to control insect pests.