Data from: Introgression between divergent corn borer species in a region of sympatry: implications on the evolution and adaptation of pest arthropods

The Asian corn borer, Ostrinia furnacalis, and European corn borer, O. nubilalis (Lepidoptera: Crambidae), cause damage to cultivated maize in spatially distinct geographies, and have evolved divergent hydrocarbons as the basis of sexual communication. The Yili area of Xinjiang Uyghur Autonomous Region in China represents the only known region where O. furnacalis has invaded a native O. nubilalis range, and these two corn borer species have made secondary contact. Genetic differentiation was estimated between Ostrinia larvae collected from maize plants at 11 locations in Xinjiang Province, and genotyped using high throughput SNP and microsatellite markers. Maternal lineages were assessed by direct sequencing of mitochondrial cytochrome c oxidase subunit I and II haplotypes, and a high degree of genotypic diversity was demonstrated between lineages based on SNP genotypes. Furthermore, historical introgression was predicted among SNP genotypes only at sympatric locations in the Yili area, whereas in Xinjiang populations wherein only O. furnacalis haplotypes were detected no analogous introgressed genotypes were predicted. Our detection of putative hybrids and historical evidence of introgression defines Yili area as a hybrid zone between the species in normal ecological interactions, and furthermore might indicate that adaptive traits could spread even between seemingly divergent species through horizontal transmission. Results of this study indicate there may be a continuum in the degree of reproductive isolation between Ostrinia species, and that the elegance of distinct and complete speciation based on modifications to the pheromone communication might need to be reconsidered.

亚洲玉米螟（Ostrinia furnacalis）与欧洲玉米螟（O. nubilalis，鳞翅目：草螟科）在空间分布迥异的不同地理区域内均会对栽培玉米造成危害，且演化出了不同的烃类化合物作为性通信的核心物质基础。中国新疆维吾尔自治区伊犁地区是目前已知的唯一一处亚洲玉米螟入侵欧洲玉米螟原生分布区的区域，这两种玉米螟物种在此发生了二次接触。研究人员从新疆维吾尔自治区的11个采样点的玉米植株上采集了玉米螟幼虫，通过高通量单核苷酸多态性（SNP）与微卫星标记完成基因分型，并对种群间的遗传分化进行了估算。研究人员通过直接测序线粒体细胞色素c氧化酶亚基I和II的单倍型来评估母系谱系，基于SNP基因型的分析显示，不同谱系间存在高度的基因型多样性。进一步分析表明，仅在伊犁地区的同域分布采样点中，SNP基因型存在历史渐渗现象；而在新疆仅检测到亚洲玉米螟单倍型的种群中，并未发现类似的渐渗基因型。本研究对疑似杂交个体的检测以及历史渐渗的相关证据，将伊犁地区确定为这两个物种间开展正常生态互作的杂交带，同时也表明适应性性状或许可以通过水平传递在看似分化显著的物种间传播。本研究结果显示，玉米螟属物种间的生殖隔离程度可能存在连续谱系，而基于信息素通信修饰所形成的清晰且完整的物种形成范式，其合理性或许需要重新考量。