Assessing the Impact of Elevated Temperature on Reproductive Success in Fall Armyworm

Abstract

Climate change poses a significant threat to insect populations, with rising temperatures potentially affecting their survival, fecundity, and overall reproductive success. This study investigates the impact of elevated temperature on the reproductive success of Spodoptera frugiperda (fall armyworm), a highly destructive and invasive pest. Newly emerged adult moths were exposed to a single heat stress event at 42°C for 2 or 6 hours, simulating extreme summer conditions. Fecundity and hatching percentage were measured to assess reproductive performance under thermal stress. The results revealed a significant impact of temperature on both fecundity and hatching percentage. Fecundity was significantly reduced to 1159.5 ± 35.6 eggs when adults were exposed to 42°C for 2 hours, compared to the control group at 27°C, which exhibited a fecundity of 1376.8 ± 30.9 eggs. Interestingly, a recovery was observed in the 6-hour exposure group, where fecundity increased to 1448.7 ± 25.5 eggs, comparable to the control. In contrast, hatching percentage showed a decline under prolonged heat exposure. While the control group and 2-hour exposure group had hatching percentages of 93 ± 1.2% and 90.5 ± 0.9%, respectively, a significant reduction to 78.2 ± 0.9% was observed after 6 hours at 42°C. These findings highlight the potential for heat stress to impair reproductive output in S. frugiperda, with implications for population dynamics under climate change. The study provides critical insights into how brief periods of extreme temperatures can affect pest populations, informing pest management strategies in the context of global warming.