| Habitat fragmentation is the process by which continuous tracts of habitat are reduced to smaller, spatially distinct remnant patches. An example of habitat fragmentation that is becoming increasingly common is the creation of land-bridge islands during anthropogenic lake formation. While the dams that create these lakes have significant benefits to human well-being, the resulting habitat fragmentation caused by lake formation causes significant biodiversity loss due to these human disturbance, leading to widespread public concern. In order to know how Landscape fragmentation caused by building dam and reservoir effected on genetic diversity of insects, the samples of Dendrolimus punctatus on 20 islands and 4 mainland plots were collected in May to July of 2014 and May and July of 2015 at the Thousand-Island Lake, east China, and used simple sequence repeats(SSR) markers to measure the D. punctatus genetic diversity. The results showed as follows: the value of gene differentiation coefficient(Fst) range between 0.001 and 0.829, value of genetic distance(D) between 0.005 and 0.615, value of effective number of alleles(Ne) range between 1.189 and 2.000, value of observed heterozygosity(Ho) range between 0.000 and 0.706, value of within-population inbreeding coefficient(Fis) range between 0.094 and 1.000, value of Shannon’s information index(I) range between 0.296 and 0.693, and there had 5 island pooulations displayed a significant departure from Hardy-Weinberg equilibrium(HWE) in the form of a homozygote excess. About 96% of D. punctatus being significant(P < 0.05) with each others after sequential Bonfer correction, and genetic diversity of islands populations were significant lower than mainland. Through analysis of molecular variance(AMOVA) and analysis of linear model and parametric regression model, we find 64.09% of total genetic variance to differences among populations, and the change of D. punctatus genetic diversity resulted jointly by island size, shape, and isolation. |
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