Comparative analysis under the family Tetranychidae with two new mitochondrial genomic resources of Stigmaeopsis nanjingensis and Stigmaeopsis continentalis (Acari: Tetranychidae)

Stigmaeopsis (Acari: Tetranychidae) species with social behaviors are difficult to be identified by morphological characteristics. The lack of nucleic acid resources as well as difficulties in sample acquisition have hindered phylogenetic studies and comparative mitochondrial genome analyses. In this study, we sequenced and annotated the mitochondrial genomes of Stigmaeopsis nanjingensis (Ma & Yuan, 1980) and S. continentalis Saito & Lin, 2018 using Illumina platform and homologous structures. The new resources integrated with public representative species under the family Tetranychidae to support the comparative and phylogenetic analysis. We obtained 37 mitochondrial genes from S. nanjingensis and S. continentalis, respectively. In phylogenetic results, all species of family Tetranychidae are well-clustered and divided into three clades. Genes and relative synonymous codon usage showed strong AT bias within Tetranychidae. Atp8 was the most variable gene and cox1 was the most conserved gene among 14 spider mite species verified by nucleotide content and bias, genes pairwise identities and the nucleotide diversities.