青海湖裸鲤寄生对盲囊线虫的种群生态研究

对盲囊线虫的三期幼虫寄生在青海湖裸鲁的体腔，以扁平的透明薄囊包被，附于肠壁和肠系膜间，其种群平均密度随突主体长的增加呈指数形式增加，寄生虫种群在突主种群中呈聚集分布，且其聚集强度随寄生虫的种群平均密度增加而增加。这种分布形式与其第一中间突主锯缘真剑水蚤在青海湖中分布的不均匀性和鱼类宿主在生长过程中的食性分化有关。具体机制无法用数学模式描述，感染率的显著增加引起分布的聚集强度降低。

POPULATION ECOLOGY OF CONTRACAECUM RUDOLPHII IN THE HOST GYMNOCYPRIS PRZEWALSKII PRZEWALSKII IN QINGHAI LAKE

The THird-stage larva of Contracaecum rudolphii is found in the cavity of Gymnocyprii przewalskii przewalskii. It is wrapped in a min capsule that attaches on gut and mesentery. Its mean density increases with the increase of host body length in a power function. The over-dispersion of parasite population in host population was found, and the degree of the aggregation increases with the increase mean density. This spatial pattern is probably related to the heterogeneous distribution of the first intermediate host of parasite and the food division of the fish host (G.przewalskii przewalskii) and can not be described with mathematical model. There is a significant negative relationship between the prevalence and the negative binomial distribution parameter k, which means the rising of prevalence may result in the decline of aggregation degree.