Pedrazzini Chiara, Strasser Hermann, Zemp Niklaus, Holderegger Rolf, Widmer Franco, Enkerli Jürg
Molecular Ecology, Agroscope Zürich Switzerland.
Institute of Environmental Systems Science ETH Zürich Switzerland.
Evol Appl. 2023 Sep 1;16(9):1586-1597. doi: 10.1111/eva.13588. eCollection 2023 Sep.
The European cockchafer is an agricultural pest in many European countries. Populations have a synchronized 3 or 4 years life cycle, leading to temporally isolated populations. Despite the economic importance and availability of comprehensive historical as well as current records on cockchafer occurrence, population genomic analyses of are missing. For example, the effects of geographic separation caused by the mountainous terrain of the Alps and of temporal isolation on the genomic structure of still remain unknown. To address this gap, we genotyped 475 adults collected during 3 years from 35 sites in a central Alpine region. Subsequent population structure analyses discriminated two main genetic clusters, i.e., the South Tyrol cluster including collections located southeast of the Alpine mountain range, and a northwestern alpine cluster with all the other collections, reflecting distinct evolutionary history and geographic barriers. The "passo di Resia" linking South and North Tyrol represented a regional contact zone of the two genetic clusters, highlighting genomic differentiation between the collections from the northern and southern regions. Although the collections from northwestern Italy were assigned to the northwestern alpine genetic cluster, they displayed evidence of admixture with the South Tyrolean genetic cluster, suggesting shared ancestry. A linear mixed model confirmed that both geographic distance and, to a lower extent, also temporal isolation had a significant effect on the genetic distance among populations. These effects may be attributed to limited dispersal capacity and reproductive isolation resulting from synchronized and non-synchronized swarming flights, respectively. This study contributes to the understanding of the phylogeography of an organism that is recognized as an agricultural problem and provides significant information on the population genomics of insect species with prolonged temporally shifted and locally synchronized life cycles.
欧洲金龟子是许多欧洲国家的农业害虫。其种群具有3或4年的同步生命周期，导致种群在时间上相互隔离。尽管欧洲金龟子的发生有着全面的历史和当前记录，且具有经济重要性，但对其进行的种群基因组分析却缺失。例如，阿尔卑斯山脉的山地地形造成的地理隔离以及时间隔离对欧洲金龟子基因组结构的影响仍然未知。为了填补这一空白，我们对在3年时间里从阿尔卑斯山中部地区35个地点采集的475只成年欧洲金龟子进行了基因分型。随后的种群结构分析区分出两个主要的遗传簇，即包括位于阿尔卑斯山脉东南部采集样本的南蒂罗尔簇，以及包含所有其他采集样本的西北阿尔卑斯簇，这反映了不同的进化历史和地理障碍。连接南北蒂罗尔的“雷西亚山口”是这两个遗传簇的区域接触带，突出了南北地区采集样本之间的基因组差异。尽管来自意大利西北部的采集样本被归为西北阿尔卑斯遗传簇，但它们显示出与南蒂罗尔遗传簇混合的证据，表明有共同的祖先。线性混合模型证实，地理距离以及在较低程度上的时间隔离对欧洲金龟子种群之间的遗传距离都有显著影响。这些影响可能分别归因于有限的扩散能力以及同步和不同步迁飞导致的生殖隔离。这项研究有助于理解一种被认为是农业问题的生物的系统地理学，并提供了关于具有长期时间转移和局部同步生命周期的昆虫物种种群基因组学的重要信息。
