The Research On Genetic Diversity And Genetic Structure Of Homidia Socia(collembola: Entomobryidae)in Fragmented Landscape Of The Thousand-island Lake

Habitat fragmentation is a process of ever continuous and big natural habitat changed into isolated and small patches.Habitat fragmentation was considered as one of the most important factors which threated biodiversity severely.As a type of fragmentation,land-bridge islands were treated as natural laboratory in fragmentation researches.Thousand-island Lake(TIL)is a typical fragmentation landscape which cause by dam built abound land-bridge islands.Since the habitat destruction and isolation,distributed in TIL's island that the diversity of arthropod populations will change.In this study,we in September 2014 and June to September 2015 to thousand island lake acquisition arthropods,based on the thousand island lake springtails 22 islands Low ability to migrate(Homidia socia)kind of contemplating the genetic diversity.The results showed that,Through the study of springtails COI gene fragments mitochondrial DNA,In the 22 species detected a total of 37 haplotype,type of haplotype(Hap)2 out of B7 island without distribution,each the rest of the island has a distribution,for the largest share the haplotype,the rest of the Shared haplotype value distribution in a handful of islands.through the study of genetic diversity,22 species genetic diversity level is not high,haplotype diversity between 0.065 to 0.733,By linear regression analysis,found the island area of island,island shape index,isolation and no significant correlation between genetic diversity;Tajima 's neutral inspection found that Tajima 's D value is negative,Can see thousand island lake formed in the early habitat change dramatically,the stability of the original population is broken,caused the springtails population changes greatly;22 springtails two studies show that the genetic differentiation between populations that the distribution of the Fst value is between 0.0004 to 0.9487,in 253 of the results,more than 0.05 a total of 175,69% of the total population belongs to the highly differentiation degree,and between 0 ? 0.05 logarithm of 78,accounting for 31% of the total,there are no genetic differentiation;Each species gene flow between two distribution from 0.0207 to 730.7253,Island closer between gene flow value is very big,islands distance between gene flow value is small,so,in these values found no obvious geographic structure;Testing the relationship between geographic distance and population differentiation through spatial analysis of molecular variance(SAMOVA),Could be divided into seven springtails 22 species group and did not reflect significant genetic structure(Fct has grown = 0.74047,P > 0.74047),Do not have a high level of genetic differentiation between groups,between the group of high genetic variation is 74.05%.Thus it can be seen that the geographical isolation and low ability to migrate to the genetic differentiation of springtails relationship is not too obvious.