Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
School of Biological Sciences, The University of Queensland, St-Lucia, Australia.
Proc Biol Sci. 2018 Mar 14;285(1874). doi: 10.1098/rspb.2017.2447.
Cleaning organisms play a fundamental ecological role by removing ectoparasites and infected tissue from client surfaces. We used the well-studied cleaning mutualisms involving the cleaner wrasse, to test how client cognition is affected by ectoparasites and whether these effects are mitigated by cleaners. Ambon damselfish ( collected from experimental reef patches without cleaner wrasse performed worse in a visual discrimination test than conspecifics from patches with cleaners. Endoparasite abundance also negatively influenced success in this test. Visual discrimination performance was also impaired in damselfish experimentally infected with gnathiid (Crustacea: Isopoda) ectoparasites. Neither cleaner absence nor gnathiid infection affected performance in spatial recognition or reversal learning tests. Injection with immune-stimulating lipopolysaccharide did not affect visual discrimination performance relative to saline-injected controls, suggesting that cognitive impairments are not due to an innate immune response. Our results highlight the complex, indirect role of cleaning organisms in promoting the health of their clients via ectoparasite removal and emphasize the negative impact of parasites on host's cognitive abilities.
清洁生物通过从客户表面清除外寄生虫和受感染的组织，从而发挥着基本的生态作用。我们利用研究充分的清洁共生关系，涉及清洁濑鱼，来测试客户认知如何受到外寄生虫的影响，以及这些影响是否可以通过清洁者减轻。从没有清洁濑鱼的实验性珊瑚礁斑块中收集的安汶雀鲷（）在视觉辨别测试中的表现比来自有清洁濑鱼的斑块中的同种雀鲷差。内寄生虫的丰度也对该测试的成功产生负面影响。在实验中感染 gnathiid（甲壳纲：等足目）外寄生虫的雀鲷的视觉辨别能力也受到损害。清洁者的缺失或 gnathiid 的感染均不会影响空间识别或反转学习测试的表现。与盐水注射对照组相比，注射免疫刺激脂多糖对视觉辨别性能没有影响，这表明认知障碍不是由于先天免疫反应引起的。我们的研究结果强调了清洁生物通过清除外寄生虫在促进其客户健康方面的复杂、间接作用，并强调了寄生虫对宿主认知能力的负面影响。
