Marin Sandra L, Carvajal Juan, George-Nascimento Mario
Instituto de Acuicultura, Universidad Austral de Chile, P.O. Box 1327, Puerto Montt, Chile.
J Parasitol. 2007 Apr;93(2):252-7. doi: 10.1645/GE-941R1.1.
Udonella australis is a platyhelminth that lives on the surface of the ectoparasite copepods Caligus rogercresseyi and Lepeophtheirus mugiloidis, which coexist on the Chilean rock cod Eleginops maclovinus. The absence of a planktonic oncomiracidium stage in the life cycle of udonellids may limit their dispersal ability. However, the high prevalence and intensity of U. australis on C. rogercresseyi suggest they have developed dispersal strategies to compensate for the lack of a free-living larval stage. The goals of this study were to determine the main dispersal mechanisms of U. australis in 1 copepod species and to compare the dispersal ability of U. australis between 2 different copepod species. Chilean rock cods were infected with female (without udonellids) and male (with and without udonellids) C. rogercresseyi. Other fishes were also infected with this copepod (with U. australis) and with L. mugiloidis (without U. australis). The dispersal of udonellids among copepods occurs through both intraspecific and interspecific processes. The main dispersal mechanism appears to be copepod mating; contact between same-sex individuals is less important. Intraspecific dispersal seems to be more dependent on the number of udonellids per fish than on copepod abundance, as observed for interspecific dispersal.
南方乌东绦虫是一种扁形虫，寄生于外寄生桡足类动物罗氏海虱和鲻状鱼虱的体表，这两种桡足类动物共同寄生于智利无须鳕体表。乌东绦虫生命周期中没有浮游幼虫期，这可能会限制其传播能力。然而，南方乌东绦虫在罗氏海虱上的高感染率和感染强度表明，它们已经进化出了传播策略来弥补自由生活幼虫阶段的缺失。本研究的目的是确定南方乌东绦虫在一种桡足类动物中的主要传播机制，并比较南方乌东绦虫在两种不同桡足类动物之间的传播能力。智利无须鳕感染了雌性（无乌东绦虫）和雄性（有或无乌东绦虫）罗氏海虱。其他鱼类也感染了这种桡足类动物（有南方乌东绦虫）和鲻状鱼虱（无南方乌东绦虫）。乌东绦虫在桡足类动物之间的传播通过种内和种间过程发生。主要传播机制似乎是桡足类动物交配；同性个体之间的接触不太重要。种内传播似乎比种间传播更依赖于每条鱼身上乌东绦虫的数量，而不是桡足类动物的数量。
