Data from: A DNA barcode library for North American Pyraustinae (Lepidoptera: Pyraloidea: Crambidae)

Although members of the crambid subfamily Pyraustinae are frequently important crop pests, their identification is often difficult because many species lack conspicuous diagnostic morphological characters. DNA barcoding employs sequence diversity in a short standardized gene region to facilitate specimen identifications and species discovery. This study provides a DNA barcode reference library for North American pyraustines based upon the analysis of 1589 sequences recovered from 137 nominal species, 87% of the fauna. Data from 125 species were barcode compliant (>500bp, <1% n), and 99 of these taxa formed a distinct cluster that was assigned to a single BIN. The other 26 species were assigned to 56 BINs, reflecting frequent cases of deep intraspecific sequence divergence and a few instances of barcode sharing, creating a total of 155 BINs. Two systems for OTU designation, ABGD and BIN, were examined to check the correspondence between current taxonomy and sequence clusters. The BIN system performed better than ABGD in delimiting closely related species, while OTU counts with ABGD were influenced by the value employed for relative gap width. Different species with low or no interspecific divergence may represent cases of unrecognized synonymy, whereas those with high intraspecific divergence require further taxonomic scrutiny as they may involve cryptic diversity. The barcode library developed in this study will also help to advance understanding of relationships among species of Pyraustinae.

尽管草螟科（Crambidae）螟蛾亚科（Pyraustinae）的类群多为重要的农业害虫，但其物种鉴定往往颇具难度，原因在于多数物种缺乏显著的诊断性形态特征。DNA条形码（DNA barcoding）技术通过利用一段标准化短基因区域的序列多样性，助力标本鉴定与物种发现工作。本研究基于对137个已命名物种（占该类群北美区系的87%）所获得的1589条序列的分析，构建了针对北美螟蛾亚科类群的DNA条形码参考数据库。其中125个物种的序列符合条形码标准（序列长度>500bp，核苷酸歧异度<1%），99个分类单元形成了独立的聚类簇，并被归为单个BIN（条形码索引号，Barcode Index Number）。剩余26个物种则被分配至56个BIN，这反映出频繁出现的种内序列深度歧异现象，以及少量条形码共享的情况，最终共计产生155个BIN。本研究选取了两种操作分类单元（OTU，Operational Taxonomic Unit）命名系统——ABGD（自动条形码间隙发现，Automatic Barcode Gap Discovery）与BIN，用于检验当前分类学体系与序列聚类结果之间的一致性。在界定近缘物种方面，BIN系统的表现优于ABGD；而ABGD所得OTU的数量会受到相对间隙宽度参数取值的影响。种间歧异度较低或无歧异的不同物种，可能存在尚未被认知的同物异名现象；而种内歧异度较高的类群则需要开展进一步的分类学审查，因为它们可能蕴含隐存多样性。本研究构建的条形码参考数据库，还有助于深化我们对螟蛾亚科物种种间关系的认知。