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格局改变，可促进生态位扩张并加速昆虫物种的适应性演化。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，推动了生态分化与初期寄主转换进程。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）清晰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反映了农业活动的遗留印记，包括作物种植（甘蔗与玉米）扩张、害虫的无意传播以及田间管理措施。与之相对，K=3则体现了采自甘蔗与玉米的幼虫之间的初期寄主分化。我们对种群规模变化的估算结果显示，约200年前的甘蔗产量下降与历史种群瓶颈事件存在关联。然而，我们检测到1950年代之后发生了更近的种群扩张事件，这与大规模作物种植向未开垦土地的农业扩张进程密切相关。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，检测到由环境（如寄主植物）驱动的遗传隔离模式。农业生产对甘蔗螟虫的影响仍将持续，当前的种群结构可能会削弱庇护所作物在延缓昆虫对Bt毒素产生抗性演化方面的功效。