| Elateridae (Coleoptera:Polyphaga:Elateroidea) are abundant throughout the world and exhibit a unique startling defense mechanism called "clicking." Elateridae is the largest family of the Elateroidea superfamily and includes approximately 400 genera and 9000 species. Lots of which are dry land pests and widely distributed in China, otherwise, some species of clickbeetles are predatory insects. Lots of different classification systems have been proposed based on the external appearance of adults and larave, however, many researchers recognized the diffculty of classifying the Elateridae based on the external appearance. Significance of The study on systematics among clickbeetles which is not only for theoretical but also practical value in insects resources usage, plant protection and pest control.1. In this study, we collected Elateridae samples from 7 provinces from middle and south of China mainland. We identified the samples based on the Kishii (1987) system based on the external appearance of adults and this system includes 12 subfamilies. The difference between our system and Kishii’s is that we replced Aplastinae by Oestodinae. We improved the DNA extraction method and compared the effect of extraction of samples in different storage conditions. The sequences was amplified via polymerase chain reaction and sequencing. The overall DNA extraction methods for the samples comprised, then 12 subfamilies and 81 species were extracted for 28S rDNA,11 subfamilies and 78 species for ITS-2 fragments.2. We saved 793bp of 28S rDNA for phylogenetic analysis. There are 400 conserved sites,386 variable sites,324 parsim-informative sites and 61 singleton sites in these bases. The base average percentage content of T, C, A and G, respectively,17.6%,29.0%,18.9% and 34.5%.The result shows that G+C content higher than that of A+T content. Meanwhile,597bp sequences were saved for ITS-2 phylogenetic analysis. There are 18 conserved sites,562 variable sites,523 parsim-informative sites and 29 singleton sites in these bases. The average percentage content of T, C, A and G, respectively,18.9%,31.1%, 17.0% and 33.0%, The result shows that G+C content higher than that of A+T content also. Conversion and transversion ratio of 28S rDNA is 1.71, which is 1.51 in ITS-2 sequences. PAUP*4beta10 was used for the nucleotide composition bias with χ2 test (Chi-square test). Saturation analysis results shows that no bases replace saturated exist in 28S rDNA and ITS-2 sequence.3. We computed the genetic distance of 28S rDNA sequences in each subfamily. Agrypninae:0.0312, Cardiophorinae:0.0507, Conoderinae:0.0470, Denticollinae:0.0558, Hypnoidinae:0.0473, Melanotinae:0.034, Negastriinae:0.0714, Oxynopterinae:0.0582, Pityobiinae:0.0086, Pyrophorinae:0.092, Elaterinae:0.0602.The minimum genetic distance between Oxynopterinae and Pityobiinae is 0.0562, the maximum genetic distance between Hypnoidenae and Negastriinae is 0.1781. The average of genetic distance between each subfamily is 0.1013.The genetic distance of ITS-2 sequences in each subfamily, respectively, Agrypninae:0.2788, Cardiophorinae:0.1076, Denticollinae: 0.1534, Hypnoidinae:0.0473, Melanotinae:0.034, Negastriinae:0.1818, Oxynopterinae: 0.0182, Pyrophorinae:0.0865, The minimum genetic distance between Oxynopterinae and Pityobiinae is 0.0182, the maximum genetic distance between Hypnoidenae and Negastriinae is 0.2424.4. According to the results of the analysis of genetic distance between each subfamily, based on two molecular markers, we constructed phylogenetic tree use three methods. It’s suggested that the conservative and variability of 28S of rDNA fragments are well used for phylogenetic analysis. Otherwise, because of the high variation, the ITS-2 sequences are more suitable for application in the lower-level taxa.This work suggested that Pityobiinae and Hypnoidenae should be in subfamily Oxynopterinae and Denticollinae. We also supported that Agrypninae, Conoderinae and Pyrophorinae should combine into one subfamily. According to the results of phylogenetic analysis, the opinion was supported that some differences exist between the phylogenetic tree and the traditional systems. It’s suggested that subfamily Pityobiinae should into Oxynopterinae as a family, the same as Denticollinae to the Denticollinae. Three subfamilies Agrypninae, Conoderinae and Pyrophorinae should be merged into one subfamily Pyrophorinae. Meanwhile, we also support Oestodinae be treated as a subfamily. In this paper, we discussed the difference between the current study and previous ones is that the applied samples in the current study support the multiple origins occurrence of Elateridae. Elateridae is widely recognized as a monophyletic group; this theory is strongly supported by studies on molecular systematics.5. In this study, the complete mitochondrial genome of a fungus-growing termite, Macrotermes natalensis, with the total length of 16,325 bp, is reported for the first time. This mtgenome harbors 13 protein-coding genes,22 transfer RNA genes,2 ribosomal RNA genes, and 1 control region (D-loop). The total base composition is 44.1% of A, 21.5% of T,11.5% of G, and 22.9% of C, so the percentage of A and T (65.6%) is much higher than that of G and C. Most of the genes are distributed on H-strand, except for four subunit genes (ND1, ND4, ND4L, ND5) and eight tRNA genes.The Postman Butterfly(Heliconius melpomene) is one of the heliconiine butterflies found in Central and South America. In this study, the complete mitochondrial genome sequence of its subspecies, Heliconius melpomene rosina,is determined for the first time. Results show that this circular genome is 15,327 bp in length, and consists of 13 protein-coding genes (PCGs),22 transfer RNAs (tRNAs),2 ribosomal RNAs (rRNAs) and 1 putative control region (D-loop). The genome organization, nucleotide composition and codon usage are identical to those reported from other butterfly mitochondrial genomes. The whole nucleotide composition is39.33% of A,42.33% of T,10.88% of C and 7.46% of G, with a relatively lower level of G and an extremely higher AT content of 81.66%. |
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