A mitogenomic phylogeny of satyrid butterflies and complete mitochondrial genome of Oeneis urda (Lepidoptera: Nymphalidae: Satyrinae)

Abstract

Oeneis urda (Eversmann, 1847) is a butterfly of the Satyrinae (Lepidoptera: Nymphalidae) and a member of the Arctics, which are distributed in the arctic, subarctic, or high-altitude alpine regions. Here, we present the complete mitochondrial genome of O. urda assembled from next-generation sequencing data. The mitochondrial DNA (mtDNA) of O. urda is a circular molecule of 15,248 bp and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one control region. Phylogenetic analysis using whole mitogenomic data of 23 satyrid butterflies strongly supports that the genus Oeneis has a close relationship with Davidina.

Keywords:

• Mitochondrial genome
• mitogenomic phylogeny
• Oeneis urda
• Satyrinae

Oeneis, a cold-adapted butterfly genus of the subfamily Satyrinae in the Nymphalidae, is widely distributed across the Arctic and mountains of the Holarctic region (Kleckova et al. 2015). There are over 30 species in the genus Oeneis (Kleckova et al. 2015) and about one-third of them can be found in Northern China (Lukhtanov and Eitschberger 2000; Wu and Hsu 2017). The species in Oeneis share similar appearance and ecological environments (Kleckova et al. 2015) although the species boundaries and evolutionary relationships among closely related species remain poorly defined (Kim et al. 2013; Warren et al. 2016). Compared with the limited number of short mitochondrial or nuclear markers, whole mitogenomes possess relatively rich genetic information and have provided further resolution for phylogenetic relationships especially within closely related species (Qin et al. 2015; Sullivan et al. 2017). In this study, the complete mitogenome of Oeneis urda is characterized. Moreover, we present the largest mitogenomic phylogeny of satyrid butterflies so far, which would contribute to studies of mitogenomic evolution and phylogeny in butterflies.

An individual O. urda was collected from Tieqiao Forest Farm (E113.34, N37.45; Elevation 1490 m), Heshun County, Shanxi Province, China on 9 May 2019 (voucher number: BL_YZ_JYD_001, kept in Nanjing Forestry University). Total genomic DNA was extracted and we followed the major protocol in our previous study (Chen et al. 2020) for genomic library construction and sequencing. The generated reads were filtered, trimmed, and mapped to reference mitogenomes of Davidina armandi and Hipparchia autonoe and then assembled using Geneious Prime^® 2019.2.1. The average sequencing coverage is about 1200×. We performed automatic annotation using the MITOS web server (Bernt et al. 2013) and manually verified the start and stop codons of genes by aligning and comparing the mitogenome of O. urda with closely related species.

To explore the phylogenetic position of O. urda on a butterfly tree, we collected 22 published mitogenomes of Satyrinae butterflies and nine outgroups from Genbank. Using the whole mitochondrial genome alignments excluding gappy (i.e., column occupancy < 0.2) and highly ambiguous D-loop regions, a phylogenetic tree was built in RAxML v8.2.10 (Stamatakis 2014) with the GTRGAMMA model and 200 ultrafast bootstraps (-f a). The maximum-likelihood (ML) tree highly supported (100%) the phylogenetic position of our sample as sister to Davidina armandi (Figure 1). In addition, all Satyrinae butterflies form a monophyletic clade with 100% bootstrap support, which further successively group with Charaxinae and Calinaginae in the Nymphalidae. This result is consistent with previous studies using hybrid capture-based genomic data (Espeland et al. 2018), morphological and small scale molecular data (Heikkilä et al. 2012).

Figure 1. Inferred phylogenetic relationships among Satyrinae butterflies based on whole mitogenome alignment excluding extremely gappy and ambiguous regions. The domestic silkworm Bombyx mori was used as the outgroup. Bootstrap value at nodes is 100% unless indicated on the tree. GenBank accession numbers of all species used in this study are shown by the species name.

The complete mitochondrial DNA of O. urda is a circular molecule of 15,248 bp in length with 20.0% GC content. It encodes 37 genes including 13 protein-coding genes, the standard 22 tRNAs, two ribosomal RNA genes, and a putative control region (GenBank accession number: MN917147). The characteristics of the gene order and intergenic spacers in the O. urda mitogenome are the same as that of other Satyrinae butterflies (Yang et al. 2020).

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This study was supported by Social Development Research Program of Jiangsu Province Science and Technology Department [No. BE2019773], Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and Hainan Key Research and Development Program [No. ZDYF2018143 to B.L.].