Dezfuli Bahram S, Maynard Barbara J, Wellnitz Todd A
Dipartimento di Biologia, Università di Ferrara, Via L. Borsari 46, Ferrara 44100, Italy.
Folia Parasitol (Praha). 2003 Jun;50(2):129-34. doi: 10.14411/fp.2003.023.
The acanthocephalan parasite Pomphorhynchus laevis (Müller, 1776) uses freshwater amphipods as its intermediate host. In order to complete the life cycle, the infected amphipod must be consumed by a fish, where the acanthocephalan will mature and reproduce. Parasite transmission, and therefore fitness, could be enhanced if infected amphipods fail to detect or avoid predatory fish. We compared the activity levels of infected and non-infected amphipods, Echinogammarus stammeri (Karaman, 1931), in both the presence and absence of odours from its natural, definitive host, the fish Leuciscus cephalus (L.). Throughout the experiment, infected amphipods were more active than were non-infected individuals. The non-infected amphipods reduced their activity after the addition of fish odours, but the infected amphipods failed to show a significant decrease. The failure of infected amphipods to reduce activity levels in the presence of fish odour may reflect a parasite strategy to increase its chances of transmission by making its amphipod host more vulnerable to predation by fish.
棘头虫寄生虫平滑膨吻棘头虫（庞弗勒希虫，1776年，米勒）以淡水端足类动物作为中间宿主。为了完成生命周期，受感染的端足类动物必须被鱼类吞食，在鱼类体内棘头虫将成熟并繁殖。如果受感染的端足类动物无法察觉或避开掠食性鱼类，那么寄生虫的传播以及适应性就可能会增强。我们比较了受感染和未受感染的斯氏棘肢钩虾（卡拉曼，1931年）在有和没有其天然终宿主——头鱼（白鲑）气味的情况下的活动水平。在整个实验过程中，受感染的端足类动物比未受感染的个体更活跃。添加鱼的气味后，未受感染的端足类动物降低了它们的活动水平，但受感染的端足类动物并没有显著减少活动。受感染的端足类动物在有鱼气味的情况下未能降低活动水平，这可能反映了一种寄生虫策略，即通过使其端足类宿主更容易被鱼类捕食来增加其传播的机会。
