中文摘要：

从2004年8月到2005年11月在丹江口水库调查的847尾马口鱼（Opsariichthys bidens）肠道内共检得寄生蠕虫14种，其中线虫7种，复殖吸虫4种，棘头虫2种，绦虫1种。该寄生蠕虫群落以广谱性寄生虫为主。杜父鱼驼形线虫（Camallanus cotti）、鳙头槽绦虫（Bothriocephalus acheilognathi）、卡斯杆咽线虫（Rhabdochona cascadilla）和木村小棘吻虫（Micracanthorhynchina motomurai）为群落的核心种。研究结果表明，寄生蠕虫群落随着马口鱼的体长和食性的改变而发生显著的变化。群落核心种的感染强度与马口鱼体长呈显著性相关。种间相关性分析表明群落结构呈非随机组合，种间感染强度存在显著的相关性。同时群落种间关系受到马口鱼的体长和食性以及季节变化的显著影响。群落种群间在宿主较大个体或夏秋季节中更容易形成显著的种间相关性。

英文摘要：

Many parasite community structures in fish have been demonstrated non-random, but the results were not consistent at any time. Some environmental factors and host traits are likely to influence the parasite community structure. Here, we address this question using data on the intestinal helminthes community of the Chinese hooksnout carp Opsariichthys bidens from the Danjiangkou Reservoir, China,and focus on the impactions caused by host body length and season variation. During the time from February 2004 to November 2005,848 specimens of O. bidens were collected and examined. In total, 14 species of the intestinal helminths were found： 7 nematodes,4 digeneans,2 acanthocephalans and 1 cestode. The result showed that 87.49% of O. bidens were parasitized by at least one parasite species and the mean intensity was 8.71 ± 11. 557. The mean infracommunity diversity was Brillouin index = 0. 238± 0. 287. The infracommunity diversity showed significantly positive correlation with host＇s total length （ Spearman rank correlation coeffection r = 0.09,p 〈 0.05） , but prevalence showed not apparent negatively correlation （ Pearson correlation coefficient r = 0. 390,p 〉 0.05） . The nematodes Camallanus cotti and Rhabdochona cascadilla, the cestode Bothriocephalus acheilognathi, and the acanthocephalan Micracanthorhyynchina motomurai with higher prevalence and intensity were the core species of this community. The infection intensities of the core species were significantly correlated with the host＇s body length （r = 0. 238, -0. 159,0. 150, -0. 115 ;p 〈0.05）. Spearman rank correlation and chi-square tests indicated there were significantly positive or negative correlations between the core species. Both of the two methods supported that the intensities between C. cotti and R. cascadilla, R. cascadilla and M. motomurai showed significantly positive or negative correlations （p 〈 0.05）. The parasite community structure of O. bidens were proved to be not random. Variation of the Spearman＇s rank