长江丽棘虫在粗唇鱼危肠道内分布的研究

对 1 0 8尾粗唇鱼危肠内长江丽棘虫种群的研究表明 ,粗唇鱼危体长 8 0～ 1 2 0cm组长江丽棘虫感染率是 88 9% ,体长 1 2 1～ 2 9 3cm感染率为 1 0 0 %。随着粗唇鱼危体长增长 ,其感染长江丽棘虫的感染强度增大。长江丽棘虫种群主要由 2 5～ 6 5mm长度的虫体组成 ,种群中雌虫显著多于雄虫。 84 0 %的虫体附着在粗唇鱼危肠道的前段。长江丽棘虫在不同体长段的宿主中均呈聚集分布 ,聚集强度各不相同。

长江丽棘虫在长吻鮠幼体中寄生的研究

长江中游长吻鱼危幼体长江丽棘虫感染率高达 84 5 % ,感染强度为 1 6 4 (1～ 48)。 1龄长吻鱼危感染率 96 3% ,感染强度 1 7 1 ;2龄鱼为 76 6 %、1 5 6 ;3龄鱼体内未检出长江丽棘虫。 80 %长江丽棘虫集丛分布在长吻鱼危小肠的前段 ,雌体明显多于雄体。

长江丽棘虫种群生态的研究

Total number of 76 Pseudobagrus fulvidraco (Richardson) caught in Huangzhou along the Yangtze River from June to July in 1998 were examined for infection by Brentisentis yangtzensis . The infection rate of the host was 30.3% and the intensity of infection was 60. The infection rate of female host was higher than that of male,but the difference of parasite intensity between female and male host was not significant. The parasite intensity of the host with body length within 23cm increased notably with increasing of the body length,but the parasite intensity of the host with body length above 23cm decreased rapidly and no Brentisentis yangtzensis was found in the host with body length above 31cm. Distribution of Brentisentis yangtzensis was clumped in the host population. The 90.3% of the parasite was distributed in first 1/3 intestinal portion of the host. The population structure pattern of the parasite looked like a pyramid. The parasitism did not cause obvious difference of condition factor in the hosts.

长江黄州江段长须黄颡鱼肠道内寄生棘头虫的生态研究

解剖检查了 133尾捕自长江黄州江段的长须黄颡鱼 ,发现寄主感染长江丽棘虫的感染率为 4 8.9% ,感染强度为 5 .4 (虫 /尾 ) ,平均密度为 2 .6 (虫 /尾 ) ,感染鲇异棘虫的感染率为 2 1.8% ,感染强度为 5 .5 (虫 /尾 ) ,平均密度为1.2 (虫 /尾 ) ,两种棘头虫在长须黄颡鱼种群中均为聚集分布 ;当两种棘头虫共同寄生在宿主肠道内时 ,其感染强度和单独感染时相比没有显著差异 ,但是 ,各自的生态位宽度均变小 ;两种棘头虫的正关联关系显著。

黄颡鱼肠道内寄生棘头虫位置分布的研究

长江丽棘虫和黄颡异钩棘头虫单独在黄颡鱼肠中分布的相似性比例PS =0 684。它们共同寄生在黄颡鱼肠道内 ,长江丽棘虫的寄生部位向前移 ,黄颡异钩棘头虫的寄生部位明显向后移 ,生态位宽度变窄 ,生态位重叠值下降。但是 ,它们的平均感染强度并未降低 。