Comparative analysis of mitogenomes among six species of grasshoppers (Orthoptera: Acridoidea: Catantopidae) and their phylogenetic implications in wing-type evolution.

The degree of wing development has a close relationship with insects' movement ability and range, and it should also be closely related to mitochondrial-related genes. The complete mitochondrial genomes of six species of Catantopidae were sequenced, annotated and analyzed. Then, combined with 37 mitogenomes of grasshoppers, the ratio of nonsynonymous substitution to synonymous substitution (Ka/Ks) of the combined sequences of protein coding genes (PCGs) was calculated by DnaSP5, and the phylogenetic relationships were reconstructed by maximum likelihood (ML) and Bayesian (BI) methods based on PCGs+rRNAs. The results showed that the sizes of the six complete mitogenomes are Stenocatantops mistshenkoi Willemse F., 1968, 15,573 bp; Traulia lofaoshana Tinkham, 1940, 15,645 bp; Sinopodisma rostellocerca You, 1980, 15,622 bp; Anapodisma miramae Dovnar-Zapolskij, 1932, 15,189 bp; Qinlingacris elaeodes Yin & Chou, 1979, 15,221 bp; and Eozubovskya planicaudata Zhang & Jin, 1985, 15,830 bp; their structures are the same as those of Acridoidea. The AT bias of the wing-degenerated group (lobiform and apterous) is higher than that of the longipennate group, and more nonsynonymous substitutions accumulated in the wing-degenerated group than in the longipennate group (P = 0.000), which indicates that the wing-degenerated group has undergone weaker evolutionary selection than the longipinnate group. The phylogenetic tree shows that the wing-degenerated group in the Catantopidae are multiorigin and present parallel evolution.