Primary Study On The Molecular Phylogeny Of The Sawfly Family Tenthredinidae (Hymenoptera: Tenthredinoidea)

Total genomic DNA was extracted from 46 adult speciemen of Tenthredinoidea stored in 100% ethanol at -20℃using CTAB method.28S rRNA,16S rRNA and 12S rRNA were amplified by polymerase chain reaction (PCR). Total sample was 58 with 12 species downloaded from Genebank. The DNA sequences were done multiple sequences alignment by ClustalXl.83. The results showed:the length of 28S rRNA partition was 559bp, containing 88 variable positions and 52 parsimonious informative positions. The length of 16S rRNA partition was 403bp, containing 232 variable positions and 198 parsimonious informative positions. The length of 12S rRNA partition was 365bp, containing 266 variable positions and 221 parsimonious informative positions. The average base composition was computed by Mega4.0. The result showed: 16S rRNA partition and 12S rRNA partition were partial to T\A, with respectively average TA percentage 81.2% and 82.4%.By using Xyela sp., Macroxyela ferruginea, Megalodontes cephalotes, Onycholyda amplecta and Cephus pygmaeus as outgroup, and Tenthredinidae (9 subfamilies,30 genera,44 species) and its closely related families (Blasticotomidae, Argidae, Pergidae, Cimbicidae and Diprionidae) as ingroup, the 28S rRNA,16S rRNA,12S rRNA partition and combined partition were analyzed by Bayesian and NJ method to reconstruct the phylogeny of the Tenthredinidae on the molecular level. The results from Bayesian method were consistent with those from NJ method according to topologies analysis. The relationships between the species of Tenthredinidae could not be found by analyzing 28S rRNA tree. The phylogeny of Tenthredinidae based on the 16S rRNA tree was paraphyletic, with((Siobla)(Macrophya)(Pachyprotasis)) (Tenthredo (Blennocampini Busarbidea))(Lagidina) (Aglaostigma) (Allantinae excluding Allantus) (Heptamelus (Loderus Dolerus))(Athalia Arge)(Eutomostethus(Erythraspides (Aneugmenini Phymatoceropsis))). The phylogeney of Tenthredinidae based on 12S rRNA tree was(Priophorus Cladius)((Heptamelus Allantus)(Loderus Dolerus) (Athalia((Beleses(Erythraspides Busarbidea))((Blennocampa Monophadnoides) (Phymatoceropsis ((Tenthredininae excluding Siobla) (Allantinae excluding Allantus))))))). The phylogeney of Tenthredinidae based on combined sequences was monophyletic, with (((Tenthredininae excluding Siobla) (Allantinae excluding Allantus) (Phymatoceropsis (Erythraspides Aneugmenini)) (Busarbidea (Eutomostethus Siobla)) (Beleses Blennocampini)(Heptamelus (Loderus Dolerus)) (Athalia))(Cladius (Priophorus (Nesoelandria Allantus)))).After comparing the topologies of molecular phylogenetic trees and morphological phylogenetic tree, we concluded that 28S rRNA partition was not suitable for the reconstruction of phylogey of Tenthredinidae, but both 16S rRNA partition and 12S rRNA partition were suitable for the reconstruction of phylogeny of Tenthredinidae.16S rRNA partition was suitable for the species in the same tribe or genus.12S rRNA partition was suitable for the species in different subfamilies or different tribes and genera in the same subfamily. The combined sequence of the three partitions was fit for analyzing the relationships among different families and subfamilies of Tenthredinoidea.