Institute of Plant and Environmental Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China.
Pest Manag Sci. 2021 Apr;77(4):1683-1693. doi: 10.1002/ps.6188. Epub 2020 Nov 29.
The diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae), is a notorious pest of cruciferous plants. In temperate areas, annual populations of DBM originate from adult migrants. However, the source populations and migration trajectories of immigrants remain unclear. Here, we investigated migration trajectories of DBM in China using genome-wide single nucleotide polymorphisms (SNPs) genotyped using double-digest RAD (ddRAD) sequencing. We first analyzed patterns of spatial and temporal genetic structure among southern source and northern recipient populations, then inferred migration trajectories into northern regions using discriminant analysis of principal components (DAPC), assignment tests, and spatial kinship patterns.
Temporal genetic differentiation among populations was low, indicating that sources of recipient populations and migration trajectories are stable. Spatial genetic structure indicated three genetic clusters in the southern source populations. Assignment tests linked northern populations to the Sichuan cluster, and central-eastern populations to the southern and Yunnan clusters, indicating that Sichuan populations are sources of northern immigrants and southern and Yunnan populations are sources of central-eastern populations. First-order (full-sib) and second-order (half-sib) kin pairs were always found within populations, but ~ 35-40% of third-order (cousin) pairs were found in different populations. Closely related individuals in different populations were found at distances of 900-1500 km in ~ 35-40% of cases, while some were separated by > 2000 km.
This study unravels seasonal migration patterns in the DBM. We demonstrate how careful sampling and population genomic analyses can be combined to help understand cryptic migration patterns in insects. © 2020 Society of Chemical Industry.
小菜蛾（DBM），也称粉纹夜蛾，属于鳞翅目菜蛾科，是十字花科植物的一种有害昆虫。在温带地区，DBM 的年度种群由成虫迁徙而来。然而，移民的源种群和迁徙轨迹仍不清楚。本研究采用双酶切 RAD（ddRAD）测序的全基因组单核苷酸多态性（SNP）分析，来调查中国 DBM 的迁徙轨迹。我们首先分析了南部源种群和北部接收种群之间的时空遗传结构模式，然后利用主成分判别分析（DAPC）、分配测试和空间亲缘关系模式推断进入北部地区的迁徙轨迹。
种群间的时间遗传分化较低，表明接收种群的来源和迁徙轨迹稳定。空间遗传结构表明，南部源种群存在三个遗传聚类。分配测试将北方种群与四川聚类联系起来，将中东部种群与南部和云南聚类联系起来，表明四川种群是北方移民的来源，南部和云南种群是中东部种群的来源。一级（全同胞）和二级（半同胞）亲缘对总是在种群内发现，但约 35-40%的三级（表亲）对存在于不同的种群中。不同种群中密切相关的个体在约 35-40%的情况下距离为 900-1500 公里，而有些则相隔>2000 公里。
本研究揭示了 DBM 的季节性迁徙模式。我们展示了如何通过仔细的采样和种群基因组分析来帮助理解昆虫的隐秘迁徙模式。 © 2020 英国化学学会。
