Preliminary Study On Molecular Phylogeny Of Pachyneuron(Hymenoptera:Chalcidoidea:Pteromalidae)

Pachyneuron belongs to Hymenoptera,Chalcidoidea,Pteromalidae.At present,there are 60 species all over the world.It is widely distributed in every zoogeographic fauna.Of these 19 species are known from China.The tiny and complexity of diversity non-homologous similarity have made it difficult to identify.On the other hand,it's enormous that the amount of repetitive identification work.So in order to achieve quickly species identification,get evolutionary relationship and verity the validity,we conducted phylogeny analysis.In this paper,150 specimens of Pachyneuron were used as the phylogeny research objects,and the gene fragment of COI,28 S rDNA,18 S rDNA,ITS2 were preliminarily screened.Phylogeny analysis and two methods(ABGD,jMOTU)were used to study the suitability of quickly species identification and evolutionary relationship.In this study,a tatal of 133 COI sequences,145 28 S rDNA sequences,20 18 S rDNA sequences and 150 ITS2 sequences were obtained.All the data were conducted basic phylogenetic analysis.ABGD and jMOTU were used to divide molecular taxonomic unit.Mega6.0,PAUP4 and Mrbayes3.2.4 were used to construct phylogenetic trees.The trees were using Neighbor-Joining(NJ),Maximum Parsimony(MP)and Bayesian inference(BI)methods.Finally we get results as follows:18S rDNA was highly conserved with high frequency invariable site.So that it is not suitable for the Pachyneuron classification.28 S rDNA conservatism is lower than 18 S rDNA.It can combine COI gene fragment to get a better results.ITS2 is the best gene fragment to value the evolutionary relationship of Pachyneuron.According to the best phylogenytic trees,summing-up the following conclutions: Pachyneuron aphidis,Pachyneuron korlense,Pachyneuron gibbiscuta,Pachyneuron solitarium,Pachyneuron formosum,Pachyneuron I SP.,Pachyneuron E SP.,Pachyneuron H SP.and Pachyneuron F SP.are monophyletic group.While Pachyneuron grande is polyphyletic group.Among all the specimens,The number of Pachyneuron aphidis is maximum.Pachyneuron aphidis,Pachyneuron solitarium and Pachyneuron sp.different in morphology,but are clustered together.Pachyneuron C SP.and Pachyneuron D SP.are different in morphology,but also clustered together on all the trees,they may be a same species.Comparing morphology research,the consequences of phylogeny analysis and the molecular taxonomic unit divided by ABGD and jMOTU are coincident.In conclusion,COI,ITS2,28 S rDNA gene fragment analysis compared with morphology research can achieve quickly species identification.