Introduction

Invasive species pose a major threat to global biodiversity and agricultural productivity, yet the genomic mechanisms driving their rapid expansion into new habitats are not fully understood. The fall armyworm, Spodoptera frugiperda, originally from the Americas, has expanded its reach across the Old World, causing substantial reduction in crop yield. Although the hybridization between two genetically distinct strains has been well-documented, the role of such hybridization in enhancing the species’ invasive capabilities remains largely unexplored.

Objectives

This study aims to investigate the contributions of hybridization and natural selection to the rapid invasion of the fall armyworm.

Methods

We analyzed the whole-genome resequencing data from 432 individuals spanning its global distribution. We identified the genomic signatures of selection associated with invasion and explored their linkage with the Tpi gene indicating strain differentiation. Furthermore, we detected signatures of balancing selection in native populations for candidate genes that underwent selective sweeps during the invasion process.

Results

Our analysis revealed pronounced genomic differentiation between native and invasive populations. Invasive populations displayed a uniform genomic structure distinctly different from that of native populations, indicating hybridization between the strains during invasion. This hybridization likely contributes to maintaining high genetic diversity in invasive regions, which is crucial for survival and adaptation. Additionally, polymorphisms on genes under selection during invasion were possibly preserved through balancing selection in their native environments.

Conclusion

Our findings reveal the genomic basis of the fall armyworm’s successful invasion and rapid adaptation to new environments, highlighting the important role of hybridization in the dynamics of invasive species.

中文翻译：

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群体基因组学分析揭示了杂交在草地贪夜蛾快速入侵中的作用

 介绍

入侵物种对全球生物多样性和农业生产力构成重大威胁，但驱动它们迅速扩展到新栖息地的基因组机制尚不完全清楚。草地贪夜蛾（Spodoptera frugiperda）最初来自美洲，现已扩展到整个旧世界，导致农作物产量大幅下降。尽管两种遗传不同的菌株之间的杂交已经有据可查，但这种杂交在增强物种入侵能力方面的作用在很大程度上仍未得到探索。

 目标

本研究旨在探讨杂交和自然选择对草地贪夜蛾快速入侵的贡献。

 方法

我们分析了来自 432 个个体的全基因组重测序数据，涵盖其全球分布。我们确定了与侵袭相关的选择基因组特征，并探讨了它们与指示菌株分化的 Tpi 基因的联系。此外，我们在本地种群中检测到在入侵过程中经历选择性扫描的候选基因的平衡选择特征。

 结果

我们的分析揭示了原生种群和侵袭种群之间的明显基因组分化。入侵种群表现出与本地种群明显不同的均匀基因组结构，表明入侵期间菌株之间存在杂交。这种杂交可能有助于维持入侵地区的高遗传多样性，这对生存和适应至关重要。此外，入侵过程中被选择的基因的多态性可能通过其原生环境中的平衡选择而得以保留。

 结论

我们的研究结果揭示了草地贪夜蛾成功入侵和快速适应新环境的基因组基础，突出了杂交在入侵物种动力学中的重要作用。