The First Mitochondrial Genomes of the Family Haplodiplatyidae (Insecta: Dermaptera) Reveal Intraspecific Variation and Extensive Gene Rearrangement.

Abstract

Simple SummaryThe insect order Dermaptera is commonly known as earwigs. The earwigs have many interesting biological characteristics, such as epizoic on other small animals, viviparous, and maternal care on their eggs and young nymphs. The external morphology of earwigs has been studied in detail, but their genetic characteristics remain unclear. The phylogenetic position of Dermaptera among all insect orders and the inner relationship of Dermaptera are largely unsolved. To better understand the molecular characters of earwigs, we sequenced and analyzed two mitogenomes of an earwig species from the family Haplodiplatyidae. The results revealed the existence of intraspecific variation and extensive gene rearrangement events in the mitogenomes of earwigs. The phylogenetic results are partially similar to previous studies. The discoveries in this study could provide new information for the molecular diversity and mitogenomic evolution of earwigs.Haplodiplatyidae is a recently established earwig family with over 40 species representing a single genus, Haplodiplatys Hincks, 1955. The morphology of Haplodiplatyidae has been studied in detail, but its molecular characters remain unclear. In this study, two mitogenomes of Haplodiplatys aotouensis Ma & Chen, 1991, were sequenced based on two samples from Fujian and Jiangxi provinces, respectively. These represent the first mitogenomes for the family Haplodiplatyidae. The next-generation sequencing method and subsequent automatic assembly obtained two mitogenomes. The two mitogenomes of H. aotouensis were generally identical but still exhibit a few sequence differences involving protein-coding genes (PCGs), ribosomal RNA (rRNA) genes, control regions, and intergenic spacers. The typical set of 37 mitochondrial genes was annotated, while many transfer RNA (tRNA) genes were rearranged from their ancestral locations. The calculation of nonsynonymous (Ka) and synonymous (Ks) substitution rates in PCGs indicated the fastest evolving nd4l gene in H. aotouensis. The phylogenetic analyses supported the basal position of Apachyidae but also recovered several controversial clades.