| Catantopidae is the biggest family in Acridoidea (Orthptera: Caelifera). It includes 16 subfamilies, 93 genera in China, mostly distributed in Oriental realm, others in Paleoarctic realm. In this family, there are some important pests in agriculture, such as Oxya chinensis, Patanga japonica, Chondracris rosea rosea, Calliptamus abbreviatus. The systematics study of them has not only theoretical but also practical applications in grasshopper control and plant protection. Recently, some cytological, morphological systematic research works on Catantopidae have been reported. However, the molecular systematic research on Catantopidae insects is still very limited. In this study, we adopted 2 mitochondrial genes (16S and Cyt b) and nuclear gene 28S rDNA sequence as molecular markers, and reconstructed the phylogenetic relationships of 30 species of Catantopidae insects which belong to 9 subfamilies, hence providing molecular evidence for the systematic study for Catantopidae.Partial sequences of Cyt b, 16S rDNA and 28S rDNA of 30 species Catantopidae grasshoppers representing 9 subfamily and 1 outgroup species (belong to Pamphagidae) have been sequenced. The base composition, substitution saturation, base composition bias among taxa, phylogenetic signal have been tested. Incongruence between different data sets and their subdata sets has been analyzed. Reconstruction of phylogeny based on Cyt b, 16S rDNA , 28S rDNA and their combined data set using MP, NJ, ML and BI and with comparison of the trees inferred from four method draw conclusion as follows.1. It is found that there are high ratio of A+T in both of Cyt b and 16S rDNA in 30 species of Catantopidae, with 72.9% and 68.7% respectively, whereas content of A+T in 28S rDNA is only 36%. Substitution saturation analysis indicates that saturation occur in loop of 16S rDNA and the 3rd code position of Cyt b, and base bias on the 3rd position of Cyt b among taxa. Strong phylogenetic signal exist in 3 subdata sets and combined data set by PTP and g1 testing. It is found that there are additive of g1 in subdata sets. So does gl of the combined data set, with value less than that of Cyt b. The phenomenon may be caused by conflict among the subdata sets.2. ILD test shows significant incongruence between loop of 16S rDNA and the 3rd position of Cyt b, the correlative co-efficiency draw the reversal conclusion. Further analyses suggest that there is potential congruence between 16S rDNA and Cyt b,incongruence caused by evolutionary noise. Thus, both of them can be used for combined analysis.3. MPT, NJT, MLT and BIT were constructed based on 3 data sets and combined data set. Comparing these trees, there are some difference between trees from each other, and that of combined data set.4. The combined unweighted tree was tested by PBS test. The branch supports for combined trees are 73.9% for 16S rDNA, 82.6% for 28S rDNA, and 86.9% for Cyt b respectively. The value of PBS is much higher than the support value of topology. The low of support value of the topology is caused by substitution saturation, base composition bias, compensating substitution.5. The MPT obtained form down weighted on the 3rd positions of Cyt b, loop and stem regions of 16S rDNA with 0 or 0.5 value, compared with unweihted MPT show that the noise of these subdata sets does not affect the topology of combined tree, and suggest combined trees is more robust.6. Based on combined data set, MP, NJ, ML and BI method were separately used to reconstruct the phylogenetic relationships of the 26 Catantopidae insects, and KH test based on likelihood method was used to compare the tree topologies produced by different methods. The result of KH test indicates that all trees based on combined data set have no significant difference in topologies, and each of them can be reasonable in the explanation of phylogenetic relationships among taxa. Based on the trees constructed from 4 methods, we can conclude:(1) The relationship of 9 subfamilies can be described as: ((Melanoplinae, Podisminae,)(((Caryandinae,Oxyinae),Coptocrinae,((CallipIaminae,Eyprepocnemidina), Cyrtacanthacridinae)), Catantopinae)).(2) Eyprepocnemidinae is a paraphyletic group and Podisminae is a polyphyletic group. We proposed to merge them into one subfamily.(3) Sinopodisma isn't a monophyletic group, and need further studies with more data.(4) Oxyinae is allied to Caryandinae and both subfamilies need to clarify whether they are monophyletic respectively.(5) The monophyly of Coptocrinae is not supported and Traualia should be moved out of Coptocrinae.(6) Traualia and Catantops form a clade. It is uncertain that these genera should be...
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