Patterns of genetic differentiation in Colorado potato beetle correlate with contemporary, not historic, potato land cover
Patterns of genetic differentiation in Colorado potato beetle correlate with contemporary, not historic, potato land cover
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DOI：
10.1111/eva.12757
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发表时间：
2019-04-01
影响因子：
4.1
通讯作者：
Schoville, Sean D.
中科院分区：
文献类型：
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作者：
Crossley, Michael S.;Rondon, Silvia, I;Schoville, Sean D.
改变景观异质性可以影响连通性并改变当地种群的遗传变异，但生态变化和进化反应之间可能存在滞后。农业生态系统的时间滞后效应可能很严重，因为过去两个世纪，农业生态系统的土地覆盖发生了巨大的变化。在这里，我们评估了 150 年来害虫遗传分化模式与过去和现在农业土地覆盖变化的关系。我们利用县级农业普查报告量化了自 1850 年以来马铃薯 (Solanum tuberosum L.) 数量和土地覆盖的变化，从 7,408 个单核苷酸多态性位点获得等位基因频率数据，并比较了美国两个农业景观中历史和当代景观连通性对科罗拉多马铃薯甲虫 (Leptinotarsa decemlineata Say) 遗传分化的影响。我们发现，马铃薯土地覆盖在 1900 年代初期在威斯康星州达到顶峰，随后迅速下降和空间集中，而在 1960 年代开始，俄勒冈州哥伦比亚盆地和华盛顿州马铃薯土地覆盖的数量和范围有所增加。在这两种景观中，我们发现景观抗性对遗传分化的影响较小，但当代景观抗性的影响相对于历史景观抗性而言要大 20 倍至 1,000 倍。人口统计分析表明，各地区的人口规模轨迹基本一致，因此不太可能对每个地区观察到的人口结构模式产生不同的影响。相反，较弱的景观遗传关联可能与我们历史土地覆盖数据的粗略分辨率有关。尽管过去两个世纪农业景观发生了快速变化，但 L. decemlineata 种群之间的遗传分化似乎反映了持续的景观变化。本研究中采用的历史景观遗传框架广泛适用于其他农业害虫，并可能揭示害虫对农业土地利用变化的一般反应。
Changing landscape heterogeneity can influence connectivity and alter genetic variation in local populations, but there can be a lag between ecological change and evolutionary responses. Temporal lag effects might be acute in agroecosystems, where land cover has changed substantially in the last two centuries. Here, we evaluate how patterns of an insect pest's genetic differentiation are related to past and present agricultural land cover change over a 150-year period. We quantified change in the amount of potato, Solanum tuberosum L., land cover since 1850 using county-level agricultural census reports, obtained allele frequency data from 7,408 single-nucleotide polymorphism loci, and compared effects of historic and contemporary landscape connectivity on genetic differentiation of Colorado potato beetle, Leptinotarsa decemlineata Say, in two agricultural landscapes in the United States. We found that potato land cover peaked in Wisconsin in the early 1900s, followed by rapid decline and spatial concentration, whereas it increased in amount and extent in the Columbia Basin of Oregon and Washington beginning in the 1960s. In both landscapes, we found small effect sizes of landscape resistance on genetic differentiation, but a 20x to 1,000x larger effect of contemporary relative to historic landscape resistances. Demographic analyses suggest population size trajectories were largely consistent among regions and therefore are not likely to have differentially impacted the observed patterns of population structure in each region. Weak landscape genetic associations might instead be related to the coarse resolution of our historical land cover data. Despite rapid changes in agricultural landscapes over the last two centuries, genetic differentiation among L. decemlineata populations appears to reflect ongoing landscape change. The historical landscape genetic framework employed in this study is broadly applicable to other agricultural pests and might reveal general responses of pests to agricultural land-use change.