[The studies of the phylogeny of acridoidea based on mtDNA sequences]

The mtDNA Cyt b sequences (432 bp) were analyzed in 10 individuals from 8 different families of Acridoidea in China. The homologous sequences were compared, the used frequency of nucleotide was calculated and the molecular phylogenetic tree constructed by Neighbor-Joining method using T. japonica as outgroup. The confidence of nodes in the trees was evaluated by bootstrap (1000 replicates). These sequences were the middle part of Cyt b gene, and in the obtained sequences, A% + T% was about 70.4% and G% + C% only 29.6%. The sequence data revealed considerable variation in 177 nucleotide sites (about 41.0%) among the analyzed individuals from 8 different families. From every amino acid codon, A% + T% in the third site was higher (86.6%) than the other two sites and lower than other insects in the corresponding region. The NJ tree suggested that 11 individuals from the 8 families clustered in 4 groups, among which Gomphoceridae and Pamphagidae firstly clustered and then together with Arcypteridae and Acrididae to form group I; Cluster II was made of three species from Catantopidae, O. japonica, O. chinensis and O. intricata; Pyrgmorphidae and Oedipodidae formed group III and Chrotogonidae single as cluster IV, respectively. The phylogenetic relationships of the 8 families was: Chrotogonidae-->Pyrgomorphidae and Oedipodidae-->Catantopidae-->Acrididae-->Arcypteridae-->Gomphoceridae and Pamphagidae, which is little different from the morphological results.