| Summary: | 碩士 === 東海大學 === 生命科學系 === 103 === The fiddler crab Uca formosensis is an endemic species of Taiwan. More than a decade ago, large populations were reported in the wetlands of Tzenwen estuary, Shankang, and Shianshan mudflats. However, due to the decrease in natural habitat for human use, the population of U. formosensis gradually decreased. Until recently, there is a growing consensus to protect its habitat. However, studies on U. formosensis were mostly descriptive, focusing on the morphology, the foraging and social behavior, and the habitats. There is no report on the population genetic analysis of U. formosensis, except two studies using allozyme analysis in 1984 and 1999. These two early allozyme reported that U. formosensis has variations in the shapes of major chela. Therefore, it is necessary to determine whether there is a correlation between morphological variations in the major chela and the genetic structure in the population of U. formosensis. The goal of my study was to understand population genetic structure of U. formosensis from new molecular evidences. Thus far, I have collected 200 samples from four wetland habitats located along the west coast of Taiwan. I examined the genetic variability of U. formosensis through TE-AFLP with the aim to identify the genetic diversity of U. formosensis populations. Using the information on the genetic variations, I investigated the relationship between the morphology of the major chela and the genetic information. The result of relationship between morphology of the major chela and the genetic distance did not differ significantly. The genetic result indicated that the population of U. formosensis had high gene flow value between Sainsi and Mailiao, but the degree of gene flow between Sainsi and the other two populations (Siangshan, Chiku) is relatively low. And the gene diversity of Sainsi population (Hj= 0.083) was also lower than those of the three populations. U. formosensis have 99% genetic variation within population. The results of either population structure or PCoA analyses did not differ significantly among populations. In summary, with the high genetic variation and gene flow, there is still a chance to recover the population of U. formosensis if there is a better plan for habitat restoration.
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