Data from: Influence of historical land use and modern agricultural expansion on the spatial and ecological divergence of sugarcane borer, Diatraea saccharalis (Lepidoptera: Crambidae) in Brazil

Human-mediated changes in landscapes can facilitate niche expansion and accelerate the adaptation of insect species. The interaction between the evolutionary history of the sugarcane borer, Diatraea saccharalis Fabricius, and historical and modern agricultural activity in Brazil shaped its spatial genetic structure, facilitating ecological divergence and incipient host-shifting. Based on microsatellite data, STRUCTURE analyses identified two (K=2) and three (K=3) significant genetic clusters that corresponded to: a) a strong signal of spatial genetic structure and, b) a cryptic signal of host differentiation. We inferred that K=2 reflects the footprint of agricultural activity, such as expansion of crop production (sugarcane and maize), unintentional dispersion of pests, and management practices. In contrast, K=3 indicated incipient host differentiation between larvae collected from sugarcane or maize. Our estimates of population size changes indicated that a historical bottleneck was associated with a reduction of sugarcane production ≈200 years ago. However, a more recent population expansion was detected (>1950’s), associated with agricultural expansion of large crop production into previously unfarmed land. Partial Mantel tests supported our hypothesis of incipient host-adaptation, and identified isolation-by-environment (e.g. host plant) in São Paulo and Minas Gerais states, where sugarcane has been traditionally produced in Brazil. The impact of agricultural production on <i>D. saccharalis</i> may continue, as the current population structure may hinder the efficacy of refuge plants in delaying insect resistance evolution to Bt toxin.人类活动介导的景观变化可促进昆虫物种的生态位扩张，并加速其适应性演化进程。甘蔗螟虫（Diatraea saccharalis Fabricius）的演化历史，与巴西古今农业活动之间的相互作用，塑造了其空间遗传结构，并推动了生态分化与初期寄主转换过程。基于微卫星（microsatellite）数据，STRUCTURE群体结构分析鉴定出两个（K=2）与三个（K=3）显著遗传聚类群，分别对应：a）强烈的空间遗传结构信号，以及b）隐蔽的寄主分化信号。我们推断K=2模式反映了农业活动的遗留痕迹，例如作物种植（甘蔗与玉米）扩张、害虫的无意扩散以及田间管理措施。与之相对，K=3模式则体现了采自甘蔗与玉米的幼虫之间的初期寄主分化现象。我们对种群规模变化的估算结果显示，约200年前甘蔗产量下降引发了历史种群瓶颈事件。但在1950年代之后检测到更为显著的种群扩张事件，这与大规模农业种植向未开垦土地拓展的活动密切相关。偏曼特尔（Partial Mantel）检验验证了我们关于初期寄主适应性的假说，并在巴西传统甘蔗种植区圣保罗州与米纳斯吉拉斯州中检测到了环境隔离（例如寄主植物介导的隔离）现象。农业生产对D. saccharalis的影响仍将持续，当前的种群结构可能会削弱庇护所植物在延缓昆虫对Bt毒素产生抗性演化方面的作用效果。