The complete mitochondrial genome of Eriocampa ovata Linné, 1760 (Hymenoptera: Tenthredinidae) and phylogenetic analysis

Abstract Eriocampa Hartig, 1837 is a small genus of Tenthredinidae and its systematic position has never been fully assessed. The complete mitochondrial genome of Eriocampa ovata Linné, 1760 was described. The circular genome is 16,293 bp in length with an A + T content of 80.6%. It contains 37 genes and a 1254 bp control region with a 405 bp repetitive sequence. All the 13 protein-coding genes initiate with a typical ATN. The CR - trnI (+)- trnQ (−)- trnM(+) cluster rearranges to trnQ (−)- trnM (+)- CR -trnI(+). Phylogenetic analysis demonstrates that E. ovata and Conaspidia wangi Wei, 2015 are closely related within the subfamily of Tenthredinidae.

Comparing the above systems concerning Eriocampa, most of them regarded Eriocampa to be a member of Eriocampini and thought that it was close to Allantinae or even placing the genus directly into Allantinae, except for Wei and Nie (1998) thought that Eriocampa was not close to Allantinae but a member of Tenthredininae. In this study, we sequenced the mitochondrial genome of Eriocampa ovata Linn e, 1760 to determine the phylogenetic position of Eriocampa.
Specimens of E. ovata were collected from Villa Luganese (46.061 N, 9.025 E), Switzerland. Samples were identified by Wei Meicai (weimc@126.com) at the Asia Sawfly Museum, Nanchang (ASMN), where a voucher specimen (CSCS-Hym-MC0143) is kept. Genomic DNA was extracted from a female and sequenced using Illumina Hiseq 4000 platform by following the standard protocols. A total of 12.92 Gb raw data was yielded and used for subsequent genome assembly by MitoZ (Meng et al., 2019) and Geneious Prime 2019.2.1 (http://www.geneious.com). Genome annotation referred to the results produced by MITOS (Bernt et al. 2013), in which the starting and ending of PCGs were determined according to the results of comparative genomics. Each PCG was aligned individually with the MAFFT algorithm in the TranslatorX server (Abascal et al. 2010). The maximum likelihood method was constructed by IQTREE (Nguyen et al. 2015) with the GTR þ CAT model and Bayesian inference conducted by PhyloBayes MPI on XSEDE (Lartillot et al. 2009) was used for 13 PCGs and nine unsaturated PCGs, respectively.
The sequence yield by MitoZ was 12,065 bp long. We thoroughly checked the obtained whole sequence by assembling using Dimorphopteryx sp. (new species, unpublished) as reference sequences (mean coverage was 18,525). The 1254length control region (CR) was identified by extending both ends of the above sequence. The circular genome is 16,293 bp long and the overall A þ T content is 80.60%. Compared with the ancestral insect mitochondrial genome (Boore 1999), CR-trnI (þ)-trnQ (À)-trnM (þ) is rearranged to trnQ (À)-trnM (þ)-CR-trnI(þ). However, within this region, there is only a 9-bp intergenic sequence between trnI and nad2. The other 192 intergenic nucleotides are distributed between 19 gene pairs, with the longest being up to 41 bp between cob and trnS. All 13 PCGs utilize ATN as the start codon, while 9 PCGs end with the canonical triplet stop codon. cob and nad4l use TAG, while nad1 and nad4 end with a single T.
Phylogenetic trees constructed under four strategies constantly support the sister group relationship between E. ovata and Conaspidia wangi Wei, 2015(Qi et al., 2015. None of the results support E. ovata and Dimorphopteryx sp. originating from the same subfamily clade. It confirms the suspicion based on morphological evidence (Ross, 1937). Three results support Selandriinae, rather than Nematinae, as the sister group of E. ovata þ C. wangi. However, Selandriinae, as the most basal branch, is supported by three of the four trees. However, these ununified phylogenetic relationships all indicate that the current sampling is far from enough to solve the internal relations in Tenthredinidae (Figure 1).

Acknowledgments
We thank the members of the Lab of Insect Systematics and Evolutionary Biology (LISEB) from Jiangxi Normal University for their kind assistance. In addition, many thanks go to editors and anonymous reviewers for their constructive comments and suggestions.

Ethics statement
The collection of specimen conformed to the requirement of International ethics, which are unrestricted species. And the collection were approved by the local authorities. The process and purpose of this experimental research were in line with the rules and regulations of our institute. There are no ethical issues and other conflicts of interest in this study.

Author contributions
Zejian Li and Meicai Wei conceived the idea and designed the research, and the final approval of the version to be published; Mengmeng Liu and Min Li analyzed the data and wrote the manuscript; Mengmeng Liu revised the manuscript. All authors agree to be accountable for all aspects of the work.

Disclosure statement
No potential conflict of interest was reported by the authors. The authors alone are responsible for the content and writing of the article.

Funding
This work was supported by the National Natural Science Foundation of China (31970447), starting fund for doctoral research of Lishui University (6004LMM01Z) and special fund for scientific research of postdoctoral research station assessment in Zhejiang Province, China (2021).  (https://www.ncbi.nlm.nih.gov/) under the accession number OK287350. The associated BioProject, SRA, and Bio-Sample numbers are PRJNA764375, SRR15990418, and SAMN21501672, respectively. All related files are publicly available in figshare (https://figshare.com/account/ home#/projects/123754).