Data from: Host associated genetic differentiation in a seed parasitic weevil Rhinusa antirrhini (Coleptera: Curculionidae) revealed by mitochondrial and nuclear sequence data

Plant feeding insects and the plants they feed upon represent an ecological association that is thought to be a key factor for the diversification of many plant feeding insects, through differential adaptation to different plant selective pressures. While a number of studies have investigated diversification of plant feeding insects above the species level, relatively less attention has been given to patterns of diversification within species, particularly those that also require plants for oviposition and subsequent larval development. In the case of plant feeding insects that also require plant tissues for the completion of their reproductive cycle through larval development, the divergent selective pressure not only acts on adults, but on the full life history of the insect. Here we focus attention on Rhinusa antirrhini (Curculionidae), a species of weevil broadly distributed across Europe that both feeds on, and oviposits and develops within, species of the plant genus Linaria (Plantaginaceae). Using a combination of mtDNA (COII) and nuclear DNA (EF1-α) sequencing and copulation experiments we assess evidence for host associated genetic differentiation within R. antirrhini. We find substantial genetic variation within this species that is best explained by ecological specialisation on different host plant taxa. This genetic differentiation is most pronounced in the mtDNA marker, with patterns of genetic variation at the nuclear marker suggesting incomplete lineage sorting and/or gene flow between different host plant forms of R. antirrhini, whose origin is estimated to date to the mid-Pliocene (3.77 mya; 2.91-4.80 mya).

植食性昆虫与其取食的寄主植物所形成的生态关联，被认为是多数植食性昆虫类群分化的核心驱动因子，其作用机制为昆虫针对不同寄主植物施加的选择压力产生差异化适应。尽管已有多项研究探讨了物种级以上的植食性昆虫类群分化模式，但针对物种内部的分化格局的关注相对匮乏，尤其是那些同样依赖植物完成产卵及后续幼虫发育阶段的昆虫类群。对于那些需借助植物组织完成从幼虫发育到生殖周期全过程的植食性昆虫而言，差异化选择压力不仅作用于成虫阶段，更贯穿昆虫的整个生活史。本研究聚焦于*Rhinusa antirrhini*（Curculionidae，象甲科），该类象鼻虫广泛分布于欧洲，其取食、产卵及幼虫发育过程均依托车前科（Plantaginaceae）柳穿鱼属（Linaria）的多个植物物种。本研究结合线粒体DNA（mtDNA，COII基因）与核DNA（EF1-α基因）测序技术，以及交配实验，对*R. antirrhini*种群内与寄主相关的遗传分化证据进行评估。研究结果显示，该物种种群内存在显著的遗传变异，这一现象最合理的解释为昆虫对不同寄主植物类群产生了生态特化。该遗传分化在线粒体DNA标记中表现最为显著；核DNA标记的遗传变异模式则暗示，*R. antirrhini*的不同寄主植物种群间存在不完全谱系分选（incomplete lineage sorting）和/或基因交流现象，该类群的分化起源时间经估算可追溯至上新世中期（3.77百万年前；置信区间2.91-4.80百万年前）。