Larval diapause enhances the flight capacity in postdiapause adults of beet webworm, Loxostege sticticalis (Lepidoptera: Pyralidae).

Abstract

The beet webworm, Loxostege sticticalis (Linnaeus) (Lepidoptera: Pyralidae), a globally distributed agricultural pest, poses a significant threat to food, oil, and cash crops. This species' outbreak dynamics primarily depend on 2 biological characteristics: larval overwintering through diapause and adult long-distance migration. However, the regulatory effects of diapause on migratory capacity and their underlying mechanisms remain poorly understood. In this study, we systematically examined the flight capacity, flight muscle weight and triglyceride content in adults derived from larvae subjected to varying diapause durations (0, 2, 4, 6, 8, 10 mo). It was confirmed that while different diapause durations had no significant effect on the flight capacity of 1-d-old adults, they could substantially enhance the flight capacity of 3-d-old post-diapause adults. Correlation analysis demonstrated that diapause-induced increases in flight muscle weight and triglyceride content were positively associated with improved flight capacity in 3-d-old adults. These results establish that prolonged diapause durations promote migratory capacity in L. sticticalis, providing critical insights for developing improved monitoring strategies and integrated pest management approaches.