Mitochondrial genomes of eight Scelimeninae species (Orthoptera) and their phylogenetic implications within Tetrigoidea.

Ran Li,Xiaodong Li,Xiaoli Ying,Weian Deng,Wantao Rong

doi:10.7717/peerj.10523

Abstract

Scelimeninae is a key member of the pygmy grasshopper community, and an important ecological indicator. No mitochondrial genomes of Scelimeninae have been reported to date, and the monophyly of Scelimeninae and its phylogenetic relationship within Tetrigidae is still unclear. We sequenced and analyzed eight nearly complete mitochondrial genomes representing eight genera of Scelimeninae. These mitogenomes ranged in size from 13,112 to 16,380 bp and the order of tRNA genes between COII and ATP8 was reversed compared with the ancestral order of insects. The protein-coding genes (PCGs) of tetrigid species mainly with the typical ATN codons and most terminated with complete (TAA or TAG) stop codons. Analyses of pairwise genetic distances showed that ATP8 was the least conserved gene within Tetrigidae, while COI was the most conserved. The longest intergenic spacer (IGS) region in the mitogenomes was always found between tRNASer(UCN) and ND1. Additionally, tandem repeat units were identified in the longest IGS of three mitogenomes. Maximum likelihood (ML) and Bayesian Inference (BI) analyses based on the two datasets supported the monophyly of Tetriginae. Scelimeninae was classified as a non-monophyletic subfamily.

Highlights

Tetrigoidea, the pygmy grasshoppers, is sister to Acridomorpha and belongs to the Acrididea infraorder (Song et al, 2015; Deng, 2016; Cigliano et al, 2020)
The gene tRNAVal was not obtained for P. sichuanense, which resulted in the smallest sequence (Fig. 1)
The order of the transfer RNA genes (tRNAs) genes between COII and ATP8 was reversed, which was opposite to the ancestral insect arrangement (Drosophila yakuba) in which tRNALys preceded tRNAAsp (Clary & Wolstenholme, 1985)

Summary

Introduction

Tetrigoidea (more than 2,000 species), the pygmy grasshoppers, is sister to Acridomorpha and belongs to the Acrididea infraorder (Song et al, 2015; Deng, 2016; Cigliano et al, 2020). Members of this subfamily generally inhabit moist environments, including wetlands and forest streams, and feed on lichens, mosses, and humus (Muhammad et al, 2018; Wei, Xin & Deng, 2018). Chen et al (2018) analyzed the phylogenetic relationships among the genera of Scelimeninae with the combined dataset of COI, 16S, and 18S, their support values were relatively low. These results must be verified with better-defined molecular characteristics and larger sample size. The sequences in that study are not publicly available, all the data still be regarded as speculative

Methods

Results

Conclusion