The effect of differen carbon dioxide concentrations on the polyphagous plant pest Aphis gossypii (Glover) (Hemiptera: Aphididae)

The cotton aphid (Aphis gossypii (Glover) (Hemiptera: Aphididae)) is a polyphagous insect pest that causes significant economic losses due to its phloem-feeding behavior and ability to transmit viral diseases. In this study, the effects of elevated atmospheric carbon dioxide (CO2) concentrations on the biology of A. gossypii were evaluated. The experiments were conducted in climate-controlled chambers under three different CO2 concentrations: 400 ± 50 ppm (control), 550 ± 50 ppm, and 700 ± 50 ppm, with constant temperature (22.5 ± 1 °C), relative humidity (60 ± 5%), and a photoperiod of 16:8 (light:dark) hours. The results revealed significant differences in biological parameters such as developmental time, reproduction, and total lifespan across the different CO2 levels. Among the nymphal stages, the first and second instars exhibited the longest durations under 550 ppm CO₂ (1.43 ± 0.10 and 1.70 ± 0.99 days, respectively), while the third and fourth instars showed the longest durations under 400 ppm CO₂ (2.14 ± 0.16 and 2.04 ± 0.19 days, respectively). The longest adult longevity was recorded at 700 ppm CO₂ (18.00 ± 1.03 days), and the total lifespan was also highest at this level (24.00 ± 1.00 days).In terms of fecundity, the average number of offspring per female was 25.39 in the control group (400 ppm), while it decreased to 13.70 and 15.34 at 550 ppm and 700 ppm CO₂, respectively. The intrinsic rate of increase (rm) and net reproductive rate (R₀) were highest at 400 ppm (0.27 and 23.71, respectively), and lowest at 550 ppm (0.19 and 13.70, respectively). These findings suggest that elevated CO2 concentrations prolong the lifespan of A. gossypii, while reducing its reproductive capacity. This highlights the importance of considering the effects of climate change, particularly increased atmospheric CO2, on the population dynamics of insect pests in future pest management strategies. KEY WORDS: Aphis gossypii, CO2, Global Warming, Carbon Emission