Molecular Systematic Study On Partial Darkling Beetles Based On Sequences Of Mitochondrial 16S RDNA And 18S RDNA

Tenebrionidae is one of the biggest groups in the order Coleoptera. There are 12 subfamilies, more than 100 tribi, more than 1500 genera and about 25000 species belonging to Tenebrionidae in the world. For a long time, classificatory research and deduction of phylogenetic relationships of Tenebrionidae are based on the characteristics of external morphology all over the world. Some scholars discussed the classify status of Tenebrionidae in Coleoptera from different angles and revealed the relationships with the closer families. Classificatory system of subfamily and tribe was produced. Since 197os, the research of molecular biology has developed quickly, but the Tenebrionidae is studied weakly in this aspect. This paper will discuss the molecular phylogeny of partial Tenebrionidae according to the genetic variation of mitochondrial 16S rDNA gene and 18S rDNA gene respectively. The conclusions drawn in this paper are following:1. The phylogenetic relationships of Tenebrionidae were studied based on mitochondrial 16S rDNA gene sequences of 20 species and 18S rDNA gene sequences of 10 species respectively. The phylogenetic trees show that the molecular results are consistent with traditional classification basically2. The analysis shows that the method and result of mitochondrial 16S rDNA gene sequences analysis reflected the variation of the genetic materials and essences of thetaxa involved in the research. They can be used to identify species, and determine phylogenetic relationships in Tenebrionidae; 18S rDNA gene sequences have higher homomorphism in different tribi of Tenebrionidae. So it can be used to verify phylogenetic relationships of the taxa of tribe or the taxa above tribe.3. In the composition of mitochondrial 16S rDNA gene sequences of darkling beetles, A + T average high about 73.5%, whereas G + C relatively low about 26.5%. In 18S rDNA gene sequences, the average of G + C is slightly higher (about 52.4%) than A + T (about 26.5%).4. Comparing molecular phylogenetic relationships concluded in the paper with views of some scholars, it is considered that Alleculinae differs from the other groups of Tenebrionidae obviously and should be resumed the status of family. Meanwhile, the Alleculidae is seen as a primitive group in Tenebrionidea.5. The phylogenetic trees show that there is an obvious aggregation among different taxa. The taxa of tribe, the taxa of genus in one tribe and the taxa of species in one genus always aggregate firstly. The controversial group in morphological research is reasonably explained from molecular angles.6. The results indicate that there are closer relationships between Platyopini and Pimelini, among Strongyliini, Clodalonini and Ulomini, among Tenebrionini, Triboliini and Blaptini, between Heteratarsini and Opatrini respectively, which supports the results of traditional classification.