ABSTRACT: Interspecific associations are common in coral reefs, but those involving hydrozoans and octocorals have not been widely investigated. The hydroid Pteroclava krempfi (Hydrozoa, Cladocorynidae) lives in association with different soft coral taxa (Alcyonacea), showing a widespread distribution. However, very little information is available on the ecology of these relationships. Here, we tested for differences in the taxon-specific prevalence and habitat preference of the symbiosis and determined ecological traits of the P. krempfi-host associations in central Red Sea reefs. P. krempfi was found associated with the alcyonacean genera Lobophytum, Rhytisma, Sarcophyton and Sinularia, updating its host range and geographic distribution. The symbiosis prevalence was high in the area and especially at inshore sites compared to midshore and offshore sites. Rhytisma was the most common host, while the association with Lobophytum showed the lowest taxon-specific prevalence. P. krempfi did not show a clear preference for a specific alcyonacean size, and an increase in host size automatically led to an increase in the surface occupied by hydrozoans, although they rarely colonized more than 50% of the upper surface of the host. The spatial distribution of the hydroids on the host surface appeared related to the host genus and size as well as to the coverage of the hydroids. Despite the nature of this symbiosis requiring further investigation, P. krempfi did not seem to play a role in affecting the bleaching susceptibilities of the host colonies. The study shows that the Red Sea coral reef symbioses are more widespread than previously known and therefore deserve more attention.

中文翻译：

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环境梯度和寄主的可利用性会影响沙特阿拉伯中部红海的翼龙科动物与褐藻科动物之间的共生

摘要：种间关联在珊瑚礁中很常见，但是涉及水生动物和八爪类的关联尚未得到广泛研究。该螅Pteroclava krempfi（水螅纲，Cladocorynidae）生活在不同的软珊瑚类群（柳珊瑚目）的关联，呈现出广泛的分布。但是，关于这些关系的生态学的信息很少。在这里，我们测试了共生共生的分类单元特异性流行度和生境偏好的差异，并确定了红海中部珊瑚礁的克雷姆普菲-宿主关联的生态特征。P. krempfi发现与alcyonacean属关联Lobophytum，Rhytisma，Sarcophyton和Sinularia，更新其寄宿范围和地理分布。与中岸和近海站点相比，该地区尤其是近岸站点的共生流行率很高。风湿病是最常见的宿主，而与Lobophytum的关联显示最低的分类群特异性患病率。P. krempfi并没有显示出对特定的拟南芥大小的明显偏好，并且寄主大小的增加自动导致水生动物占据的表面增加，尽管它们很少定植于寄主上表面的50％以上。宿主表面上水合物的空间分布似乎与宿主的属和大小以及水合物的覆盖率有关。尽管这种共生的性质需要进一步研究，克氏菌似乎没有在影响宿主菌落的漂白敏感性中发挥作用。研究表明，红海珊瑚礁共生体比以前已知的更为广泛，因此值得更多关注。