Spatial heterogeneity in parasite loads in the New Zealand cockle: the importance of host condition and density
Spatial heterogeneity in parasite loads in the New Zealand cockle: the importance of host condition and density
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新西兰鸟蛤寄生虫负载的空间异质性：寄主条件和密度的重要性
DOI：
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发表时间：
2003
影响因子：
1.2
通讯作者：
R. Poulin
中科院分区：
文献类型：
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作者：
K. Mouritsen;S. Mckechnie;E. Meenken;J. Toynbee;R. Poulin
在两个不同的潮间带水平收集的新西兰海扇Austrovenus stutchburyi（Veneridae）的样品被发现严重感染棘口吸虫Curtuteria australis，其中使用泥滩螺Cominella glandiformis和滨鸟作为第一和最终宿主，分别。寄生虫负荷平均高2倍以上，在高网站比在低网站，而每平方米的Curtuteria australis囊蚴密度表现出相反的趋势。这种模式似乎与第一中间宿主和C.澳大利亚人在该宿主体内的流行率在不同地点之间没有差异。在这两个网站有一个寄生虫负载和扇贝条件之间的正相关关系，一个可能的副产品之间的关系条件为基础的过滤能力和速度，个别的扇贝遇到自由游泳的吸虫幼虫。结果表明，寄生率的网站之间的变化是一个结果，更高的密度在低网站的鸟蛤。在那里，密集的海扇种群能够清除水柱中的寄生虫，因此个体海扇实际上“竞争”寄生虫幼虫。这将降低平均感染强度，但提高平均寄生虫密度每平方米。
Samples of the New Zealand cockle Austrovenus stutchburyi (Veneridae) collected at two different intertidal levels were found to be heavily infected by the echinostome trematode Curtuteria australis which use the mud flat whelk Cominella glandiformis and shorebirds as first and definitive host, respectively. Parasite loads were on average more than 2-fold higher at the high site than at the low site, whereas the density of Curtuteria australis metacercariae per square metre showed the opposite trend. This pattern appeared unrelated to the abundance of first intermediate hosts and C. australis prevalence within this host that did not differ between sites. At both sites there was a positive relationship between parasite load and cockle condition, a likely by-product of the relationship between condition-based filtration capacity and the rate at which individual cockles encounter the free-swimming trematode larvae. The results suggest that the between-site variation in parasitism is a consequence of the much higher density of cockles at the low site. There, the dense cockle population is able to clear the water column of parasites and consequently individual cockles virtually ‘compete’ for parasite larvae. This will depress mean infection intensity per cockle but elevate mean parasite density per square metre.