# Genomic Analysis Reveals Annual Variation in the Migratory Pathways to East Asia in the Brown Planthopper (Nilaparvata lugens)

## TL;DR

The study shows that brown planthoppers in East Asia have varying migratory patterns each year, originating from different tropical regions.

## Contribution

The study reveals annual variation in BPH migratory pathways using population genomics data from multiple years and regions.

## Key findings

- BPH migration into East Asia involves genomically distinct overwintering origins with annual variation.
- Population genomics analyses identified two major groups with significant genetic differentiation.
- Ancestry analysis confirmed complex ancestry patterns among East Asian BPH populations.

## Abstract

The brown planthopper (BPH,
Nilaparvata lugens
) is a major rice pest in Asia, causing significant yield losses. As BPH cannot overwinter in temperate regions, East Asian populations are wind‐borne migratory insects originating from tropical regions. The identification of precise migratory patterns is essential for forecasting BPH outbreaks and implementing effective pest management strategies. Despite extensive studies using meteorological data, field population observations, and whole‐genome analyses, the BPH migratory pathways to East Asia remain unclear. To address this question, we conducted population genomics analyses using 454 BPH individuals densely collected from China, Korea, and Vietnam between 2017 and 2022. We showed that BPH migration into East Asia exhibits substantial annual variation and involves genomically distinct overwintering origins. Principal component analysis revealed two major groups with whole‐genome differentiation. This separation was confirmed by statistically significant F
ST estimates, suggesting migration pathways involving at least two overwintering populations. Ancestry coefficient analysis further confirmed the complexity of the ancestry of East Asian BPH. These results demonstrate the complex migratory dynamics of East Asian BPH populations, possibly with the influence of differential selective pressures among overwintering origins. Given the heterogeneity of migratory pathways to East Asia, we argue for temporally and geographically dense field monitoring with the incorporation of genetic information to enhance early warning and BPH management strategies.