Muzzall P M, Whelan G E, Taylor W W
Department of Zoology, Michigan State University, East Lansing 48824.
J Parasitol. 1992 Oct;78(5):837-44.
A total of 1,115 longnose dace, Rhinichthys cataractae (family Cyprinidae), were examined for parasites from May 1983 through October 1986 from 3 localities in the Ford River in Michigan's Upper Peninsula. Thirteen parasite species (1 Monogenea, 2 Digenea, 2 Cestoda, 4 Nematoda, 1 Acanthocephala, 3 Protozoa) infected dace. The parasite faunas of dace, taxonomically and in species number, were similar between localities. Posthodiplostomum minimum minimum, Neascus sp., and Rhabdochona canadensis were the most common helminths infecting dace from each locality. The first 2 species did not exhibit consistent seasonal infection patterns between years, whereas the prevalence and mean intensity of R. canadensis in dace from the downriver locality were higher in summer 1983, 1984, and 1985. The intensity of infection of each of these helminth species significantly increased with host length. The prevalences and mean intensities of P. m. minimum, Neascus sp., and R. canadensis as well as the helminth infracommunity diversity were highest in dace from the upriver locality. The major factors that influenced parasite intensity were environmental factors that occurred when and where a fish began its life, the sequence of events that occurred in each habitat the fish encountered during its life, and the length of exposure (age of fish). Dace have isolationist helminth infracommunities arising from factors including ectothermy, a simple enteric system, restricted vagility, and being gape-limited. Allogenic helminths with indirect life cycles predominate in the depauperate helminth fauna of dace.
1983年5月至1986年10月期间，在密歇根上半岛福特河的3个地点，共检查了1115条长吻雅罗鱼（Rhinichthys cataractae，鲤科）的寄生虫。有13种寄生虫（1种单殖吸虫、2种复殖吸虫、2种绦虫、4种线虫、1种棘头虫、3种原生动物）感染了雅罗鱼。不同地点雅罗鱼的寄生虫区系在分类学和种类数量上相似。微小后双盘吸虫最小亚种（Posthodiplostomum minimum minimum）、新杯叶吸虫属（Neascus sp.）和加拿大似锥吻线虫（Rhabdochona canadensis）是感染各地雅罗鱼最常见的蠕虫。前两种寄生虫在不同年份之间没有呈现出一致的季节性感染模式，而1983年、1984年和1985年夏季，下游地点雅罗鱼体内加拿大似锥吻线虫的感染率和平均感染强度较高。这些蠕虫种类的感染强度均随宿主长度显著增加。微小后双盘吸虫最小亚种、新杯叶吸虫属和加拿大似锥吻线虫的感染率、平均感染强度以及蠕虫群落多样性在来自上游地点的雅罗鱼中最高。影响寄生虫感染强度的主要因素包括鱼类开始生活时的环境因素、鱼类在其生命过程中遇到的每个栖息地发生的事件序列以及暴露时间（鱼的年龄）。雅罗鱼具有隔离主义的蠕虫群落，这是由包括变温性、简单的肠道系统、有限的游动性和口裂限制等因素导致的。在雅罗鱼贫乏的蠕虫区系中，具有间接生命周期的异源蠕虫占主导地位。
