Department of Zoology, University of British Columbia, 2370-6270 University Blvd., Vancouver, BC, Canada V6T 1Z4.
Mol Ecol. 2010 Mar;19(6):1122-33. doi: 10.1111/j.1365-294X.2010.04548.x. Epub 2010 Feb 15.
Trichoplusia ni is a subtropical moth that migrates annually from southern California to southern British Columbia, Canada where it invades vegetable greenhouses and field crops. The heated greenhouse environment has altered the natural extinction-recolonization dynamics of T. ni populations, and allows year-round persistence in some locations. In addition, the extensive use of the biopesticide, Bacillus thuringiensis subspecies kurstaki (Bt) in some greenhouses has selected for resistance. Here we investigated the genetic structure of T. ni populations in British Columbia greenhouses and in field populations in California and British Columbia using amplified fragment length polymorphisms (AFLP) as related to patterns of Bt resistance. The majority of British Columbia field populations were similar to the California field populations, the potential source of migrants. However populations in two geographic areas with high concentrations of greenhouses showed local genetic differentiation. Some of these populations experienced severe bottlenecks over-winter and following Bt sprays. Greenhouse populations showed a pattern of isolation by distance and a strong positive relationship between genetic differentiation and levels of Bt resistance. These patterns indicate that greenhouses that sometimes support year-round populations of T. ni and the ensuing strong bottlenecking effects following winter cleanups and Bt application cause genetic differentiation of T. ni populations. Long distance migrants to field populations contribute to genetic homogeneity of these.
斜纹夜蛾是一种亚热带飞蛾，每年从加利福尼亚州南部迁徙到加拿大不列颠哥伦比亚省南部，在那里它入侵蔬菜温室和大田作物。温室环境的升温改变了斜纹夜蛾种群的自然灭绝-再殖民动态，并使其在某些地方能够全年持续存在。此外，在一些温室中大量使用生物农药苏云金芽孢杆菌亚种 kurstaki（Bt）选择了抗性。在这里，我们使用扩增片段长度多态性（AFLP）研究了不列颠哥伦比亚省温室中的斜纹夜蛾种群和加利福尼亚州和不列颠哥伦比亚省田间种群的遗传结构，这些种群与 Bt 抗性模式有关。大多数不列颠哥伦比亚省田间种群与加利福尼亚州田间种群相似，是迁徙者的潜在来源。然而，在两个温室集中的地理区域的种群显示出局部遗传分化。其中一些种群在冬季和 Bt 喷雾后经历了严重的瓶颈。温室种群表现出距离隔离的模式，遗传分化与 Bt 抗性水平之间存在强烈的正相关关系。这些模式表明，有时支持斜纹夜蛾全年种群的温室以及冬季清理和 Bt 应用后的强烈瓶颈效应导致了斜纹夜蛾种群的遗传分化。长途迁徙到田间种群的飞蛾有助于这些种群的遗传同质性。
