Spatial genetic structure of the mountain pine beetle (Dendroctonus ponderosae) outbreak in western Canada: historical patterns and contemporary dispersal

Environmental change has a wide range of ecological consequences, including species extinction and range expansion. Many studies have shown that insect species respond rapidly to climatic change. A mountain pine beetle epidemic of record size in North America has led to unprecedented mortality of lodgepole pine, and a significant range expansion to the northeast of its historic range. Our goal was to determine the spatial genetic variation found among outbreak population from which genetic structure, and dispersal patterns may be inferred. Beetles from 49 sampling locations throughout the outbreak area in western Canada were analysed at 13 microsatellite loci. We found significant north-south population structure as evidenced by: (i) Bayesian-based analyses, (ii) north-south genetic relationships and diversity gradients; and (iii) a lack of isolation-by-distance in the northernmost cluster. The north-south structure is proposed to have arisen from the processes of postglacial colonizati...环境变化可引发广泛的生态后果，涵盖物种灭绝与分布范围扩张。多项研究表明，昆虫物种对气候变化的响应极为迅速。北美地区曾爆发规模创纪录的山松甲虫（mountain pine beetle）疫情，导致扭叶松（lodgepole pine）出现史无前例的大量死亡，且该甲虫的分布范围已向其历史分布区东北部发生显著扩张。本研究旨在明确爆发种群间的空间遗传变异，借此推断其遗传结构与扩散模式。研究人员对加拿大西部疫情发生区域内49个采样点的山松甲虫样本，基于13个微卫星位点（microsatellite loci）开展了遗传分析。结果显示存在显著的南北向种群遗传结构，具体证据包括：(1) 基于贝叶斯（Bayesian-based）方法的分析结果；(2) 南北向的遗传关系与多样性梯度；(3) 最北部种群集群未出现距离隔离（isolation-by-distance）现象。我们推测该南北向种群结构源于冰期后拓殖……