Interannual and seasonal migration patterns of wheat aphids across the Bohai Strait in eastern Asia based on ten years of monitoring data

The bird cherry-oat aphid (Rhopalosiphum padi) and the grain aphid (Sitobion miscanthi) are two destructive wheat pests that have caused severe economic losses in China's main wheat-producing regions. Although previous studies have focused mainly on the population dynamics of wheat pests in wheat fields, little is known about the trans-sea migration of both wheat aphids in eastern China. Here, we conducted a 10-year monitoring from 2012 to 2021 to determine for understanding the aerial migration patterns of both wheat aphids utilizing a suction trap on Beihuang Island (BH), a small island in the center of the Bohai Strait that serves as a seasonal insect migration pathway in eastern Asia. We also simulated the migration trajectories of these pests using the HYSPLIT model. Overall, a total of 6362 alatae S. miscanthi and 335 alatae R. padi were captured, and both wheat aphids exhibited regular patterns of comigration across the sea during late April to late October each year. There were significant interannual and seasonal differences in the migratory numbers of both wheat aphids. Notably, the average daily humidity was the most important meteorological factor affecting migration biomass. The seasonal migration trajectories simulated using the HYSPLIT model revealed different source areas for both wheat aphid species, which mostly originated in Northeast, North and East China. Accordingly, our study provides valuable insights into the occurrence and migration route of wheat aphids in eastern Asia, helps fine-tune forecasting and early warning systems, and thereby guides integrated pest management of wheat aphids in China.鸟樱桃蚜（Rhopalosiphum padi）与禾谷缢管蚜（Sitobion miscanthi）是两类毁灭性小麦害虫，曾在中国小麦主产区造成严重经济损失。尽管既往研究多聚焦于麦田小麦害虫的种群动态，但学界对中国东部这两种麦蚜的跨海迁飞行为仍知之甚少。为此，本研究于2012至2021年开展了长达10年的监测工作，借助位于渤海海峡中部的北隍城岛（BH）的吸捕装置，探究两种麦蚜的空中迁飞模式——该岛是东亚地区季节性昆虫迁飞的关键通道。本研究同时利用HYSPLIT模型对上述害虫的迁飞轨迹进行了模拟。本次监测共捕获有翅禾谷缢管蚜6362头、有翅鸟樱桃蚜335头；两类麦蚜均呈现出每年4月下旬至10月下旬规律性跨海共迁飞的特征。两种麦蚜的迁飞数量均存在显著的年际与季节差异。值得注意的是，日均湿度是影响迁飞生物量的最关键气象因子。通过HYSPLIT模型模拟得到的季节迁飞轨迹显示，两种麦蚜的起源地存在差异，其主要虫源均来自中国东北、华北及华东地区。综上，本研究为东亚麦蚜的发生规律与迁飞路线提供了重要见解，有助于优化预测预警系统，进而为中国麦蚜的综合防治提供指导。