Seasonal Migration Pattern of Nilaparvata lugens (Hemiptera: Delphacidae) Over the Bohai Sea in Northern China.

The brown planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) is a major, regionally migratory pest of rice crops in Asia. Despite intensive studies, the seasonal pattern of migration in this species remains largely unknown, especially in northern China. Analysis of monitoring data of light trapping at Beihuang island in northern China showed that brown planthopper migrants could be found at the island in any month from July to October. However, the daily number of brown planthopper migrants varied considerably from day to day, month to month, and year to year. Most of migrants were caught from July to September, with fewer in October. Simulation of backward trajectories showed that there was temporal variation in the source areas of brown planthopper migrants trapped at Beihuang. A majority of migrants trapped at Beihuang in July came from south of Beihuang. In contrast, migrants caught in August and September could be from any direction around the island. Results suggested that the brown planthopper migrants likely traveled northward in July, and Multidirectionally in August and September in northern China. Some of brown planthopper in northeastern China could escape the 'Pied Piper effect' and migrate southward in September.