Aquaculture and Fisheries Group, Department of Animal Sciences, Wageningen University and Research Centre , 6709 PG Wageningen , The Netherlands.
Biol Open. 2013 Jan 15;2(1):10-7. doi: 10.1242/bio.20122741. Epub 2012 Oct 26.
Many scleractinian coral species host epizoic acoelomorph flatworms, both in aquaculture and in situ. These symbiotic flatworms may impair coral growth and health through light-shading, mucus removal and disruption of heterotrophic feeding. To quantify the effect of epizoic flatworms on zooplankton feeding, we conducted video analyses of single polyps of Galaxea fascicularis (Linnaeus 1767) grazing on Artemia nauplii in the presence and absence of symbiotic flatworms. 18S DNA analysis revealed that flatworms inhabiting G. fascicularis belonged to the genus Waminoa (Convolutidae), which were hosted at a density of 3.6±0.4 individuals polyp(-1). Polyps hosting flatworms exhibited prey capture rates of 2.2±2.5, 3.4±4.5 and 2.7±3.4 nauplii polyp(-1) 30 min(-1) at prey concentrations of 250, 500 and 1,000 nauplii L(-1), respectively. Polyps that had their flatworms removed displayed prey capture rates of 2.7±1.6, 4.8±4.1 and 16.9±10.3 nauplii polyp(-1) 30 min(-1). Significant main and interactive effects of flatworm presence and ambient prey concentration were found, reflected by the fact that flatworms significantly impaired host feeding rates at the highest prey density of 1,000 nauplii L(-1). In addition, flatworms displayed kleptoparasitism, removing between 0.1±0.3 and 0.6±1.1 nauplii 30 min(-1) from the oral disc of their host, or 5.3±3.3 to 50.0±2.1% of prey acquired by the coral. We suggest classifying the coral-associated Waminoa sp. as an epizoic parasite, as its presence may negatively affect growth and health of the host.
许多珊瑚纲物种在水产养殖和原位环境中都有共生的后生动物扁形虫。这些共生扁形虫可能通过遮荫、去除黏液和破坏异养摄食来损害珊瑚的生长和健康。为了量化共生扁形虫对浮游动物摄食的影响，我们对 Galaxea fascicularis （Linnaeus 1767）单个珊瑚虫吞噬卤虫无节幼体的过程进行了视频分析，分析过程中存在和不存在共生扁形虫。18S DNA 分析显示，栖息在 G. fascicularis 上的扁形虫属于 Waminoa 属（Convolutidae），其密度为 3.6±0.4 条/珊瑚虫。有扁形虫的珊瑚虫的猎物捕获率分别为 2.2±2.5、3.4±4.5 和 2.7±3.4 个无节幼体/珊瑚虫 30 分钟（-1），猎物浓度分别为 250、500 和 1000 个无节幼体 L（-1）。去除扁形虫的珊瑚虫的猎物捕获率分别为 2.7±1.6、4.8±4.1 和 16.9±10.3 个无节幼体/珊瑚虫 30 分钟（-1）。扁形虫的存在和环境中猎物浓度的主要和交互作用有显著影响，这反映了一个事实，即在最高猎物密度 1000 个无节幼体 L（-1）时，扁形虫显著损害了宿主的摄食率。此外，扁形虫还表现出盗食行为，每 30 分钟从宿主的口盘上偷走 0.1±0.3 到 0.6±1.1 个无节幼体，或珊瑚虫获得的猎物的 5.3±3.3% 到 50.0±2.1%。我们建议将与珊瑚相关的 Waminoa sp. 归类为外寄生寄生虫，因为它的存在可能会对宿主的生长和健康产生负面影响。
