Classification Of The Genus Xylosandrus Reitter Inferred Based On Chinese Specimens

The genus Xylosandrus belonging to Curculionidae Scolytinae Xyleborini, we past commonly known as "Xyleborina". Most Xylosandrus species can cause large economic losses for the local forest systems and agricultural systems. All Xylosandrus genus(non-Chinese species) has been included in China's Ministry of Agriculture of the entry plant quarantine pest list. Classification of Xylosandrus genus can contribute to these economic pests accurately identified.The genus Xylosandrus currently contains greater difference on most morphological including species currently, Some species are very close, such as X. crassiusculus?X. compactus?Xylosandrus germanus, several of which are similar to those of other genera, leading to confusion concerning the generic boundaries of Xylosandrus and its relationship to and distinction from the genera Amasa, Anisandrus, and Cnestus. In this study, we described the Xylosandrus spp located in China respectively, and clarified Xylosandrus genus of China species, specifically Xylosandrus genus of China species. Discussed on the status Xylosandrus genus based on this Xylosandrus genus of specimens by molecular tools. Last we analyzes the X. discolor between the seven geographic populations of the mitochondrial gene cytochrome oxidase I(COI), 28 S rDNA,and the nuclear genes rudimentary(CAD). The results are as follows:We collected the Xylosandrus genus specimens from forest in southwest China six provinces and check some related Documents. This paper describes six species of Xylosandrus genus based on specimens collected and laboratory-reared, and given the classification characteristic graph and distribution, and a brief description of biological information of four kinds species from Xylosandrus genus are given. Research shows that some of China Xylosandrus genus species have spread out more than the original distribution, the new distribution of X. discolor are: Yunnan(Jinping,Hekou), Sichuan(Chengdu), Chongqing, Guizhou(Xingyi), Jiangxi(Nanchang, Zhangshu); the new distribution of X. crassiusculus are: Yunnan(Jinping,Hekou); the new distribution of X. germanus are: Sichuan(Dechang), Jiangxi(Nanchang); the new distribution of X. mutilatus are: Jiangxi(Nanchang). Southern provinces Forestry sector need attention for the intrusion of Xylosandrus genus to prevent a more serious ecological damage.The status of the genus Xylosandrus exist highly questionable from its founding. In this study, we used the Xylosandrus genus specimens from forest in southwest China six provinces and the specimens of the approximate genus to Xylosandrus genus to amplify the mitochondrial gene cytochrome oxidase I(COI), 28 S rDNA,and the nuclear genes rudimentary(CAD), constructing a phylogenetic hypothesis of the species,further discuss the rationality of taxonomic status. The genetic distance between the genus Xylosandrus of three kinds of genetic marker genes is too large, far greater than generally belong to the species genetic distance between species. Three genetic marker genes between species genetic average distance are: 0.168?0.030?0.082. Xylosandrus genus did not like the other species, the interspecific relationships in the same genus are close, to come together in the development of the tree, but showing divergent. The species of the genus Xylosandrus were broken up into three communities, during which also mixed with species of the genera Xyleborus, Xyleborinus and Cnestus. Three labeled gene COI, 28 S, CAD all reflect the complex and confusing genetic relationship of the genus Xylosandrus.X. discolor is one of the important quarantine pests damage trees. We analyzes the X. discolor between the seven geographic populations of the mitochondrial gene cytochrome oxidase I(COI), 28 S rDNA, and the nuclear genes rudimentary(CAD) in this study,and combined with Vietnam's X. discolor data, analyzes X. discolor the possible genetic branch in China. The results show that China have nine haploid type, COI sequences shows large genetic differences among different geographic populations,and 28 s and CAD sequence is highly conserved. Confirmed that the X. discolor of Chongqing population may be on the verge of interspecific differentiation. The research results can be for our country's X. discolor of genetic differentiation and invasion pathways to provide the reference.