Original paper
The timing of heatwave and drought impact on reproductive success and offspring fitness in oriental armyworm, Mythimna separata
Lv, Weixiang; Zhang, Huan; Jiang, Chen; Stanley, David; Zhang, Lei
Entomologia Generalis Volume 45 Number 2 (2025), p. 493 - 503
published: May 22, 2025
published online: May 15, 2025
manuscript accepted: Mar 4, 2025
final revised version received: Feb 18, 2025
manuscript revision requested: Feb 11, 2025
manuscript received: Nov 8, 2024
DOI: 10.1127/entomologia/2025/3157
Open Access (paper may be downloaded free of charge)
Abstract
Heatwaves and droughts are increasing in frequency and magnitude, which diminishes insect reproduction and offspring fitness. However, the underlying response mechanisms are still poorly understood, especially for the timing of heatwaves, and compound effects of drought and heatwave. Here, we investigate whether heat-related reproductive impairments are timing- or drought-dependent by exploring the effect of the timing of heatwaves and droughts within a short time frame on reproductive success and offspring fitness in Mythimna separata, a notorious agricultural pest. We found that heatwave exposure during mating led to greater damage to reproductive success and offspring fitness relative to heatwave exposure before or after mating. Heatwave exposure before mating damaged reproductive success, but not offspring fitness. In contrast, exposure to a heatwave event after mating had no effect on reproductive performances, but negatively influenced offspring fitness. Compared to a heatwave or drought alone, individuals exposed to heatwaves and droughts (32 °C for 3 days and 35% RH) suffered a significant reduction in reproductive success and water content, and a significant increase in glycogen and triglyceride content accumulation. We emphasize the point that variations in the timing of a heatwave or the combination (heatwave and drought) can lead to different consequences for insect reproduction, and suggest the accumulation of energy substances may contribute to buffering drought and heatwave stress in insects. Our findings can improve predictions on the ecological consequences of heatwaves and droughts on agricultural pests under climate change.
Keywords
global warming • abiotic stress • reproduction • two-sex life table • climate change