Effects of elevated CO on the fitness and potential population damage of Helicoverpa armigera based on two-sex life table.

We evaluated the direct effects of three different atmospheric CO concentrations (380 ppm, 550 ppm and 750 ppm) on the population parameters of the cotton bollworm, Helicoverpa armigera fed an artificial diet. The life history and fitness of H. armigera were analyzed using an age-stage, two-sex life table. Our results showed significantly longer larval durations and lower female pupal weight under elevated CO than under ambient CO. Additionally, the fecundity of H. armigera was lower under elevated CO than under ambient CO. H. armigera reared under elevated CO conditions showed lower intrinsic and finite rates of increase but higher net consumption and finite consumption rates than H. armigera reared under ambient CO conditions. According to population projections, a much smaller total population size and reduced consumption capacities would be expected in an elevated CO atmosphere due to higher mortality and lower growth rate compared with ambient CO levels. These results indicate that the fitness of and potential damage caused by H. armigera would be affected by increased CO relative to ambient CO concentrations. Additional studies on the long-term direct and indirect effects of elevated CO levels on H. armigera are still needed.