Multidimensionality in host manipulation mimicked by serotonin injection

Manipulative parasites often alter the phenotype of their hosts along multiple dimensions. ‘Multidimensionality’ in host manipulation could consist in the simultaneous alteration of several physiological pathways independently of one another, or proceed from the disruption of some key physiological parameter, followed by a cascade of effects. We compared multidimensionality in ‘host manipulation’ between two closely related amphipods, Gammarus fossarum and Gammarus pulex, naturally and experimentally infected with Pomphorhynchus laevis (Acanthocephala), respectively. To that end, we calculated in each host–parasite association the effect size of the difference between infected and uninfected individuals for six different traits (activity, phototaxis, geotaxis, attraction to conspecifics, refuge use and metabolic rate). The effects sizes were highly correlated between host–parasite associations, providing evidence for a relatively constant ‘infection syndrome’. Using the same methodology...

操控性寄生虫（Manipulative parasites）通常会从多个维度改变宿主表型（host phenotype）。宿主操控的“多维性（multidimensionality）”，既可表现为多条生理通路（physiological pathways）彼此独立地同时发生改变，也可源于某一关键生理参数（key physiological parameter）的紊乱，进而引发一系列级联效应（cascade of effects）。本研究对两种近缘端足类动物（amphipods）——富氏钩虾（Gammarus fossarum）与普通钩虾（Gammarus pulex）——分别自然感染与实验感染光滑泡吻棘头虫（Pomphorhynchus laevis，棘头动物门Acanthocephala）后的宿主操控多维性进行了比较。为此，我们针对每种宿主-寄生虫组合（host–parasite association），计算了感染个体与未感染个体在6项性状上的差异效应量（effect size），这6项性状分别为活动能力（activity）、趋光性（phototaxis）、趋地性（geotaxis）、同种吸引行为（attraction to conspecifics）、庇护所利用（refuge use）以及代谢率（metabolic rate）。不同宿主-寄生虫组合间的效应量呈高度相关，这为存在相对恒定的“感染综合征（infection syndrome）”提供了证据。本研究采用相同方法……