Influence of Sublethal Carbon Dioxide on Biological Characteristics and Life Table Parameters of Cynaeus angustus...

Understanding insect survival and developmental characteristics in sublethal carbon dioxide (0.25-4%), which could exist in stored grain, is beneficial to scientific pest management. The survival, developmental duration, oviposition, and life table parameters of Cynaeus angustus (LeConte) were measured with carbon dioxide at 0.25%, 0.5%, 1%, 2%, and 4% in air, respectively, and 0.04% as a control. The developmental duration at 4% of carbon dioxide was 87 days versus 90 days in control at 23 °C, 79 days versus 85 days in control at 28 °C. The generation survival rate varied from 77% to 69% at 23 °C, and from 81% to 74% at 28 °C in the concentrations. The number of eggs laid per female reduced from 28 in the control to 19 in 4% of carbon dioxide. The sex ratio decreased from 1.19 and 1.21 to below 1.0 at 4% of carbon dioxide at the tested temperatures. Life table parameters (T, R₀, r, λ) were significantly decreased at and above 0.5% carbon dioxide at 23 °C; r and λ were significantly decreased at 2% carbon dioxide at 28 °C. Carbon dioxide above 0.25% or 0.5% significantly affected the survival and development, which may affect fumigation or controlled atmosphere with this sublethal carbon dioxide.