Abstract: A total of 22 species (representing 10 subfamilies and 16 genera) and an outgroup species, Filchnerella sunanensis, were sampled in this study. A 585 bp sequence of COⅡ gene was amplified using PCR, and then sequenced directly through cycling sequencing method. Several statistical approaches were used to test the phylogenetic signal in the DNA sequence data sets and three partition data sets, which were defined based on different codon positions. Phylogenetic analyses by the Neighbor Joining (NJ), maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI) were employed to reconstruct the phylogeny. The results indicated that the COⅡ gene sequences of 22 species were highly A+T biased. All of the different data sets contained strong phylogenetic signal. It can be found from the consensus tree that: (1) the relationships among Calliptaminae, Cyrtacanthacridinae, Eyprepocnemisinae and Catantopinae are close. (2) The relationship between Caryandinae and Oxyinae is also close. It is so reasonable to include the subfamily Caryandinae into the subfamily Oxyinae, with Spathosterninae as sister group. (3) Melanoplinae should merge with Podisminae into one subfamily. (4) The relationships of species and genera within Coptacrinae, as well as its relationships with other subfamilies were not resolved. (5) The relationship between Melanoplinae and Podisminae is close, and both are distant to other subfamilies here studied. The results prove that COⅡ gene is a useful marker to infer phylogenetic relationships among species and genera within a subfamily.

Key words: Orthoptera, Catantopidae, COⅡ gene, molecular evolution, phylogeny