Department of Biology, University of Victoria, Victoria, BC, Canada.
Sci Rep. 2022 Oct 26;12(1):17923. doi: 10.1038/s41598-022-22872-z.
The threespine stickleback (Gasterosteus aculeatus) is an important model for studying the evolution of vertebrate morphology. Sticklebacks inhabit freshwater, brackish, and marine northern hemisphere waters. Anadromous and marine populations (hereafter marine) are assumed to have remained unchanged morphologically from ancestral marine sticklebacks, despite marine environments varying on regional and local scales. Recent studies suggest that genetic and phenotypic structure exists in marine populations, yet the scale of this variation, and its ecological causes remain unclear. Our goal was to assess morphological trait variation in marine stickleback populations around Southern British Columbia (BC) and determine if oceanographic and habitat characteristics were associated with this variation. Between May-July 2019, we sampled 534 sticklebacks from 15 sites around Vancouver Island, a region characterized by a large diversity of oceanographic and habitat features. We characterized trait variation using two-dimensional (2D) geometric morphometric analysis, comparing individuals between oceanographic regions and habitats. We focused on head and body shape. We found that marine sticklebacks varied morphologically among and between regions and habitats, but the variation did not appear to be related to environmental variation. Sexual dimorphism was the largest source of variation, but oceanographic and habitat variables influenced differences between sexes. We concluded that marine sticklebacks offer abundant opportunities for expanding our knowledge of drivers of morphology.
三刺鱼（Gasterosteus aculeatus）是研究脊椎动物形态进化的重要模式生物。三刺鱼栖息于淡水、半咸水和北温带海洋水域。尽管海洋环境在区域和局部尺度上存在差异，但人们认为溯河洄游和海洋种群（以下简称海洋种群）在形态上与祖先的海洋三刺鱼保持不变。最近的研究表明，海洋种群中存在遗传和表型结构，但这种变异的规模及其生态原因仍不清楚。我们的目标是评估南不列颠哥伦比亚省（BC）周围海洋三刺鱼种群的形态特征变异，并确定海洋特征和生境特征是否与这种变异相关。2019 年 5 月至 7 月，我们从温哥华岛的 15 个地点采集了 534 条三刺鱼，该地区具有丰富的海洋和生境特征多样性。我们使用二维（2D）几何形态测量分析来描述特征变异，比较不同海洋区域和生境的个体之间的差异。我们重点关注头部和身体形状。研究发现，海洋三刺鱼在区域和生境之间存在形态上的差异，但这种差异似乎与环境变化无关。性二型性是变异的最大来源，但海洋和生境变量影响了两性之间的差异。我们得出结论，海洋三刺鱼为扩展我们对形态驱动因素的认识提供了丰富的机会。
