Accurate identification of species is a prerequisite for successful biodiversity management and further genetic studies. Species identification techniques often require both morphological diagnostics and molecular tools, such as DNA barcoding, for correct identification. In particular, the use of the subunit I of the mitochondrial cytochrome c oxidase (COI) gene for DNA barcoding has proven useful in species identification for insects. However, to date, no studies have been carried out on the DNA barcoding of Nigerian butterflies. We evaluated the utility of DNA barcoding applied for the first time to 735 butterfly specimens from southern Nigeria. In total, 699 DNA barcodes, resulting in a record of 116 species belonging to 57 genera, were generated. Our study sample comprised 807 DNA barcodes based on sequences generated from our current study and 108 others retrieved from BOLD. Different molecular analyses, including genetic distance-based evaluation (Neighbor-Joining, Maximum Likelihood and Bayesian trees) and species delimitation tests (TaxonDNA, Automated Barcode Gap Discovery, General Mixed Yule-Coalescent, and Bayesian Poisson Tree Processes) were performed to accurately identify and delineate species. The genetic distance-based analyses resulted in 163 well-separated clusters consisting of 147 described and 16 unidentified species. Our findings indicate that about 90.20% of the butterfly species were explicitly discriminated using DNA barcodes. Also, our field collections reported the first country records of ten butterfly species—Acraea serena, Amauris cf. dannfelti, Aterica galena extensa, Axione tjoane rubescens, Charaxes galleyanus, Papilio lormieri lormeri, Pentila alba, Precis actia, Precis tugela, and Tagiades flesus. Further, DNA barcodes revealed a high mitochondrial intraspecific divergence of more than 3% in Bicyclus vulgaris vulgaris and Colotis evagore. Furthermore, our result revealed an overall high haplotype (gene) diversity (0.9764), suggesting that DNA barcoding can provide information at a population level for Nigerian butterflies. The present study confirms the efficiency of DNA barcoding for identifying butterflies from Nigeria. To gain a better understanding of regional variation in DNA barcodes of this biogeographically complex area, future work should expand the DNA barcode reference library to include all butterfly species from Nigeria as well as surrounding countries. Also, further studies, involving relevant genetic and eco-morphological datasets, are required to understand processes governing mitochondrial intraspecific divergences reported in some species complexes.

正确识别物种是成功进行生物多样性管理和进一步遗传研究的前提。物种识别技术通常需要形态学诊断和分子工具（例如DNA条形码）才能正确识别。特别是，线粒体细胞色素C氧化酶的亚基I的用途用于DNA条形码的（COI）基因已被证明可用于昆虫的物种鉴定。但是，迄今为止，尚未对尼日利亚蝴蝶的DNA条形码进行任何研究。我们评估了DNA条形码首次应用于来自尼日利亚南部的735个蝴蝶标本的效用。总共产生了699条DNA条形码，记录了属于57属的116种。我们的研究样本包含807个DNA条形码，这些条形码基于我们当前研究产生的序列，而其他108个条形码则是从BOLD中检索到的。不同的分子分析，包括基于遗传距离的评估（邻域加入，最大似然法和贝叶斯树）和物种定界测试（TaxonDNA，自动条形码缺口发现，常规混合尤尔族聚居，和贝叶斯泊松树过程）进行准确地识别和描绘物种。基于遗传距离的分析得出了163个完全分离的簇，其中包括147个已描述物种和16个未识别物种。我们的发现表明，使用DNA条码可以明显地区分大约90.20％的蝴蝶。另外，我们的田间收藏报告了十种蝶类的第一个国家记录-珍蝶属小威，Amauris参见 丹芬蒂（Dannfelti），加盖大麦草（Aterica galena extensa），茜素茜草（Axione tjoane rubescens），灰背竹（Charaxes galleyanus），凤蝶凤蝶（Papilio lormieri lormeri），白蚁凤蝶（Pentila alba），Precis actia，Precis tugela和Tagiades flesus。此外，DNA条码显示，寻常双轮车和逃逸的Colotis的线粒体种内差异超过3％。此外，我们的结果显示整体单体型（基因）多样性较高（0.9764），这表明DNA条形码可为尼日利亚蝴蝶提供种群水平的信息。本研究证实了DNA条形码识别尼日利亚蝴蝶的效率。为了更好地了解这个生物地理复杂区域的DNA条形码的区域差异，未来的工作应该扩展DNA条形码参考库，以包括尼日利亚和周边国家的所有蝴蝶物种。同样，需要进一步的研究，包括相关的遗传和生态形态数据集，以了解控制某些物种复合物中报道的线粒体种内差异的过程。