Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, UK.
Parasitology. 2013 May;140(6):756-70. doi: 10.1017/S0031182012002119. Epub 2013 Feb 1.
The life cycle of the parasitic copepod Lernaeocera branchialis involves 2 hosts, typically a pleuronectiform host upon which development of larvae and mating of adults occurs and a subsequent gadoid host, upon which the adult female feeds and reproduces. Both the copepodid and adult female stages must therefore locate and identify a suitable host to continue the life cycle. Several mechanisms are potentially involved in locating a host and ensuring its suitability for infection. These may include mechano-reception to detect host movement and chemo-reception to recognize host-associated chemical cues, or kairomones. The aim of this study was to identify the role of kairomones in host location by adult L. branchialis, by analysing their behaviour in response to fish-derived chemicals. Experiments demonstrated that water conditioned by immersion of whiting, Merlangius merlangus, elicited host-seeking behaviour in L. branchialis, whereas cod- (Gadus morhua) conditioned water did not. Lernaeocera branchialis are considered a genetically homogeneous population infecting a range of gadoids. However, their differential response to whiting- and cod-derived chemicals in this study suggests that either there are genetically determined subspecies of L. branchialis or there is some form of environmental pre-conditioning that allows the parasite to preferentially recognize the host species from which it originated.
寄生桡足类动物藤壶的生命周期涉及到两个宿主，通常是幼虫发育和成虫交配发生在一种比目鱼宿主上，而随后的鳕鱼宿主则是成年雌性进食和繁殖的地方。因此，桡足幼虫和成年雌性阶段都必须找到并识别合适的宿主才能继续生命周期。有几种潜在的机制涉及到定位宿主并确保其适合感染。这些机制可能包括机械接收以检测宿主的运动，以及化学接收以识别与宿主相关的化学线索，或信息素。本研究的目的是通过分析成年藤壶对鱼类来源化学物质的反应来确定信息素在宿主定位中的作用。实验表明，用鳕鱼（Gadus morhua）浸泡条件后的水不能引起藤壶的宿主寻求行为，而用鳕鱼浸泡条件后的水不能引起藤壶的宿主寻求行为。藤壶被认为是一种感染多种鳕鱼的遗传上同质种群。然而，它们在这项研究中对鳕鱼和鳕鱼衍生化学物质的不同反应表明，要么存在遗传上确定的藤壶亚种，要么存在某种形式的环境预适应，使寄生虫能够优先识别其起源的宿主物种。
