Migration Activity of Spodoptera litura (Lepidoptera: Noctuidae) between China and the South-Southeast Asian Region.

Simple Summary: The common cutworm, Spodoptera litura, is a major migratory pest worldwide. Seasonal migration is the biological basis of its regional population outbreaks. In this study, migration dynamics and trajectory simulations were conducted from Ruili City, an important migratory corridor between China and the south Asia region. The results showed that this pest exhibited seasonal migration in this area, mainly divided into two migration periods. One seasonal migration route across multiple national borders was identified by a trajectory simulation model. These findings will help in developing regional management systems for this pest in the relevant countries. The common cutworm, Spodoptera litura (F.), feeds on a wide variety of food and cash crops and is one of the most widespread and destructive agricultural pests worldwide. Migration is the biological basis of its regional population outbreaks but the seasonal movement of this pest between east and south Asia regions remains unknown. In this study, searchlight traps were used to monitor the seasonal migration of S. litura from 2019 to 2023 in Ruili City (Yunnan, China), located along the insect migratory route between China and the south Asia region. The results showed that migratory activity could occur throughout the year, with the main periods found in spring (April–May) and autumn (October–December). The ovarian development and mating status of the trapped females indicated that most individuals were in the middle or late stages of migration and that Ruili City was located in the transit area of the long-distance migration of the pest. In the migration trajectory simulation, populations of S. litura moved from northeast India, Bangladesh, and northern Myanmar to southwestern China along the southern margin of the Himalayas in spring and returned to the south Asia region in autumn. Our findings clarify the seasonal migration patterns of S. litura in China and South Asia and facilitate the development of regional cross-border monitoring and management systems for this pest. [ABSTRACT FROM AUTHOR]