Abstract: Impacts of the rising CO₂ concentration atmosphere on growth, development, reproduction and nutritional efficiency of the cotton bollworm Helicoverpa armigera (Hübner) reared on spring wheat in the cotton region of Northern China were studied through laboratory experiment with collected milky grains (as diets) from spring wheat grown in 370 Μl/L CO₂ treatment (factually 382.4±24.8) and 750 Μl/L CO₂ treatment (factually 738.8±25.7) in open-top chambers. The results indicated: (1) As reared on grains of elevated CO₂ grown spring wheat, the larvae of cotton bollworm fed more grains and produced more frass. Compared with CK, food ingestion and frass produced by bollworm larvae increased by 46.3% P<0.05) and 37.8% respectively. (2) Elevated CO₂ affected the nutritional constitutes of grains. Significant increases were found in soluble protein, free amino acids, glucose, amylase, TSCs and ratio of TSCs: GP (gross protein) and significant decreases in fructose and gross protein compared to CK. (3) The changes in grain nutritional constitutes owing to elevated CO₂ influenced the diet utilization efficiency of bollworm larvae. Decreases were found in efficiency of conversation of ingested food (ECI) and digested food (ECD) of bollworm larvae fed on grains of elevated CO₂ grown spring wheat by 27.2% and 25.4% respectively, and significant (P<0.05) increase in relative consumption rate (RCR ) by 58.8% compared with those of larvae fed on grains of ambient CO₂ grown spring wheat. So elevated CO₂ may cause adverse impacts on nutritional values of milky grains for the development and growth of cotton bollworm, H. armigera, and the larvae may consume more wheat grains and cause in heavier damage in the rising CO₂ concentration atmosphere in future.

Key words: Helicoverpa armigera, CO, spring wheat, growth, development, reproduction, nutritional efficiency