"Physiological and demographic responses of to combined climate stressors: CO, temperature, and ozone".

Climate change factors, including elevated carbon dioxide (eCO), elevated ozone (e0), and the combined effect of elevated temperature and CO (eT+eCO), significantly influence the population dynamics, development, and feeding behavior of the Brown Planthopper (, BPH) and its impact on rice yield. A two-year field study (2019-2020) showed that BPH populations were highest under eCO (61.6 ± 13.5 and 50.6 ± 12.3 N/hill) and moderate under eT+eCO (44.5 ± 9.4 and 47.5 ± 12.1 N/hill), while e0 drastically reduced populations (17.7 ± 3.1 and 25.1 ± 7.0 N/hill). Fecundity followed a similar trend, with the highest egg production under eCO (219.7 ± 3.3 and 234.3 ± 9.7 eggs/female), moderate under eT+eCO (194.2 ± 6.3 and 223.5 ± 9.2 eggs/female), and lowest under e0 (108.4 ± 6.0 and 135.6 ± 3.7 eggs/female). Developmental duration was shortest under eT+eCO (14.9 ± 0.3 and 15.9 ± 0.4 days) and longest under e0 (18.2 ± 0.40 and 21.7 ± 0.40 days). Feeding intensity, indicated by honeydew excretion, was highest under eCO (124.8 ± 5.3 and 131.3 ± 4.2 mm²), reduced under eT+eCO (105.7 ± 4.9 and 107.6 ± 3.4 mm²), and lowest under e0 (44.2 ± 2.5 and 48.9 ± 2.6 mm²). Results indicated that eCO promoted overall plant growth, with the highest plant height (65.4 ± 0.8 cm) and reproductive tillers (22.2 ± 0.6). However, under BPH infestation, eCO also resulted in the highest yield reduction (15.9%) despite producing the highest grain yield under uninfested conditions (40.1 ± 0.3 g/hill). The eT+eCO treatment exhibited moderate reductions in plant height (62.4 ± 0.6 cm) and grain yield (38.1 ± 0.4 g/hill), with a yield loss of 11.5% under infestation. The e0 treatment negatively impacted plant growth, significantly reducing plant height (54.8 ± 1.0 cm), total tillers (17.7 ± 0.9), and grain yield (27.5 ± 0.2 g/hill) in uninfested conditions, with a lower yield reduction (8.72%) under infestation. The findings of this study indicate that pests and host plants benefited under eCO and eT+eCO conditions; however, increasing BPH populations caused yield losses. Nevertheless, e0 had a detrimental effect on pests as well as host plants. The results pertaining to the collective impact of climate change factors on both the host plant and pests have the potential to contribute to the advancement of insect pest management strategies in response to shifting climates.