缺乏遺傳變異亟待保育的津田氏大頭竹節蟲（竹節蟲目：竹節蟲科）

The distribution of Megacrania tsudai Shiraki, a threatened stick insect species in Taiwan, is limited to the Hengchun Peninsula and Green Island, with only a small population in each locality. Previous studies on this insect were mostly focused on its morphology and life history. In the present study, the 16S rDNA gene was used as a marker to study the genetic diversity, phylogenetic relationships, and phylogeography of M. tsudai. Crude DNA was extracted from 46 samples of eggs or partial mid-leg tarsi collected from three populations (Jioupeng, Kankau and Green Island). Sequence analyses of 16S rDNA, ~550bp, from 23 successfully amplified samples showed no variation at all between and within populations. This result suggests that the populations of M. tsudai in Taiwan may have either descended from a limited number of ancestors (founder effect), or have experienced a bottleneck effect due to a small population size and restricted habitats. From a conservation point of view, the perfect genetic homogeneity of the M. tsudai populations will have a negative impact on the long-term survival of this species in Taiwan. In addition to enhancing their legal protection, it would also be helpful to conserve this species by preserving its habitats and broaden its distribution range. It is also very important that we explore potential genetic variation and preserve it in the wild populations.