The complete mitochondrial genome of the grasshopper Chorthippus dubius (Zub.) (Orthoptera: Acrididae: Gomphocerinae): detailed characterization and phylogenetic position.

Chorthippus dubius (Zub.) is one of the dominant grasshopper species. The limited data on Ch. dubius (Zub.) has impeded further understanding of its genetic characteristics and molecular detection. In this study, we analyzed the mitogenome of Ch. dubius (Zub.), which was 15,561 bp in length and contained 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes and an AT-rich region. The entire mtDNA exhibited a strong AT bias, with an overall A+T content of 74.8%. The relative synonymous codon usage (RSCU) analysis revealed UUA (L) as the most frequently used codon. All the PCGs evolved under purifying selection (Ka/Ks <0.5), with ATP8 gene exhibited the highest Ka/Ks ratio. Maximum likelihood (ML) and Bayesian inference (BI) analyses reconstructed two topologically similar phylogenetic trees, and supported the monophly of the six subfamilies in Acrididae. Our results indicated two stable clades of the six subfamilies, with Oedipodinae emerging as the ancestral taxon and being sister group to the remaining taxa. In the alternative phylogenetic lineage, the remaining five subfamilies clustered the following relationship: Gomphocernae + (Acridinae + (Calliptaminae + (Melanoplinae + Oxyinae))). Both phylogenetic trees exhibited a closer relationship between Chorthippus dubius (Zub.) and Chorthippus aethalinus, members from the same genus.