1. Trajectory analysis methods were used to explore source regions and migrating pathways of rice leaf roller, Cnaphalocrocis medinalis, in China.
2. The results of release-capture experiments were analyzed with the trajectory model and biological parameters were simulated and calculated. Take-off time was dusk, 20:00 hours, flight duration was 8 - 9h per night, and successive flying time period, which varied from 1 to 7 day, could be determined by the distance between source and sink areas.
3. Source regions of rice leaf roller within Huaihe and Yangtze river rice district were estimated by backtracking flight trajectories. From early June to late August, source regions were moving gradually to the northeast, from Guangdong and Guangxi provinces to Hunan and Jiangxi provinces. During the same period, sink areas were moving from south to north within the rice district in Anhui and Jiangsu provinces. Two or more source regions may contribute to one sink area during different time periods.
4. Migration pathways were analyzed in several representative counties in the Huaihe and Yangtze river rice district. Most trajectory lines are parallel to the mountain ranges, suggesting that rice leaf rollers migrate along the mountain ranges.
5. Outbreaks of rice leaf roller in several different source regions may be very useful for predicting arrival in the sink areas. However, further improvement in the trajectory models and research on the details of migration are needed to make the prediction models in the sink areas more practical and valuable.
Key words. Migration, flight behavior, Cnaphalocrocis medinalis, rice leaf roller, trajectory, China.
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