EFFECT OF IN TRODUCED SPECIES ON BIOLOGICAL DIVERSITY : A SYNTHETIC STUDY ON A HYBRID POPOULATION OF TAIWANESE MACAQUES IN WAKAYAMA

和歌山地区台湾猕猴（Macaca cyclopis）与日本猕猴（M. fuscata）杂交，年增长率高达14%。在研究期间，它们的分布区域几乎没有扩大，从2个增加到4个。它们表现出较少的杂交破坏症状，似乎很好地适应了环境条件，这表明对当地生态系统有潜在的不利影响。相对尾长与尾椎骨数呈极显著正相关，尾形态是各个体杂交程度的良好指标。结果表明，在田间观察杂交品种的尾巴形态是评价杂种品种的重要依据。在颞间距离、门牙和磨牙大小等方面存在种间差异。在牙齿的相对大小差异上，与亲本种的变异范围相比，一些杂交种表现出非加性特征。群体遗传研究表明，在研究期间，外来基因或杂交程度不同的杂种比例的变化较少。褐斑基因和杂交个体在种群中的比例估计分别约为50%和90%。根据遗传标记的分布，杂交的触发因素可能是外来雄性日本猕猴的基因流动。两个物种的随机交配得到了两个遗传标记的支持，但另外两个遗传标记表明纯合子个体过多，这表明杂交群体中可能存在一些选择性变化。为了监测雄性迁移对杂交群体的扩展，建立了一种新的Y染色体分型方法，并将染色体上的多态微卫星DNA位点结合起来进行分型。显微镜观察发现，杂交个体的精子发生正常，表明两种猕猴之间的受精卵后生殖隔离机制发展较少。在杂交种群和野生本地种之间的传染性病毒检查没有发现差异。血液寄生虫未见疟原虫和丝虫虫。对粪便样本的检查发现了日本猕猴中常见的两种线虫卵。最后，本研究结果提出了杂交种群中各种生物学性状的新发现和猕猴物种形成中生殖隔离发展的推论，以及外来猕猴物种引入对保护管理的潜在影响的重要信息。少

The hybrids between Taiwanese (Macaca cyclopis) and Japanese (M. fuscata) macaques in Wakayama showed high annual growth rate (14 percent). They increased from two to four groups with little expansion of distribution areas during the study period. They showed less symptom of hybrid breakdown and seemed to adapt well to the environmental conditions, suggesting potential adverse effects on native ecosystems.Relative tail length and the number of caudal vertebrae showed significantly positive correlation and the tail morphology was a good indicator of the degree of hybridization for each individual. It was proved that observation of tail morphology in field could allow us to evaluate hybrids. Species differences were found in the inter-temporal distance, and the sizes of incisors and molars. In the relative size differences in teeth, some of hybrids showed non-additive profile compared to the variation ranges in parental species.Population genetic study revealed less changes in the compos … More ition of exotic genes or proportion of hybrids with various degrees of hybridization through the study periods. The proportions of fuscata genes and hybrid individuals in the population were estimated to be approximately 50 percent and 90 percent, respectively. Based on the distribution of genetic markers, the trigger of hybridization was considered to be gene flow by males of Japanese macaques came from outside areas. Random mating of two species was supported by two genetic markers, but two other markers suggested excess of homozygous individuals, suggesting a possibility of some selective changes in the hybrid population. In monitoring expansion of the hybrid population by male migration, a new method of Y chromosome typing was established and used effectively by combining polymorphic microsatellite DNA loci on the chromosome.Microscopic observations found normal spermatogenesis in hybrid individuals, indicating less development of postzygotic reproductive isolation mechanism between the two macaque species.Inspection of infectious viruses detected no difference between the hybrid population and native species in wild. For blood parasites, no worms of Plasmodium and Filaria were observed in this study. Inspection of fecal samples detected two kinds of eggs of nematodes commonly known in Japanese macaques.Finally, the results of this study presented new findings of various biological traits in the hybrid population and inference on the development of reproductive isolation in macaque speciation as well as important information on potential impact of introduced foreign macaque species for conservation management. Less