Abstract

A variety of symbionts inhabit colonies of scleractinian corals, the main component of coral reef ecosystems. Obligate symbionts spend almost their whole lives (except the pelagic larvae stage) on or in the host, while facultative symbionts are less tightly associated with the host and easily leave them when food becomes scarce and competition and predation increase. The influence of parasites on the life traits of obligate and facultative symbionts has not yet been studied. The first step in this direction is the study of basic parameters of parasite infracommunities associated with coral symbionts. It was suggested that obligate symbionts that are tightly associated with their hosts and their symbiotic communities are more often infected. An alternative hypothesis suggests that facultative symbionts are more frequently infected because they easily change habitats and consume a broad food spectrum. For several years, we studied parasites of obligate and facultative symbionts (fish, decapods crustaceans, mollusks) associated with the corals Acropora and Pocillopora in the Nha Trang Bay (South China Sea). The highest abundance and diversity of macroparasites (Monogenea, Cestoda, Trematoda, Nematoda, Copepoda) were found in facultative symbionts of corals, fish-parabionts. Obligate fish-inbionts were infected much less often (Cestoda, Trematoda, Nematoda). Obligate symbionts predominated in the invertebrate symbionts, which were also weakly infected. The low abundance and diversity of parasites in obligate symbionts suggest that there should be significant investments in antiparasitic defense, which, together with efficient antipredation defense, minimize the mortality of obligate symbionts. Their fecundity and population number are usually low. Facultative symbionts presumably suffer higher mortality than obligate symbionts, but a more intensive use of resources and higher population numbers may compensate for this. A significant increase in the infection rate with an increase in host body size is typical of facultative symbionts, which are less protected than obligate symbionts. The latter showed low infection levels in all size groups. The results suggest that the role of parasites in shaping the life strategies of symbionts is no less important than the role of predators.

中文翻译：

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巩膜珊瑚共生群落中专性和兼性共生体的大寄生虫负担

摘要

珊瑚礁生态系统的主要组成部分——Scleractinian珊瑚的殖民地中栖息着各种各样的共生生物。专性共生几乎整个生命（除上层幼虫阶段）都在宿主上或宿主中度过，而兼性共生与宿主的联系不那么紧密，并且在食物变得稀缺且竞争和捕食增加时容易离开它们。尚未研究寄生虫对专性和兼性共生者生活特征的影响。朝这个方向迈出的第一步是研究与珊瑚共生体相关的寄生虫次生物的基本参数。有人提出，与其寄主和共生社区紧密相关的专性共生体经常被感染。另一个假设表明，兼职共生体更容易受到感染，因为它们容易改变生境并消耗广泛的食物。几年来，我们研究了与珊瑚相关的专性和兼性共生体（鱼，十足纲甲壳类动物，软体动物）的寄生虫。鹿角和鹿角在芽庄湾（南海）。在珊瑚，鱼类-寄生生物的共生共生体中发现了最大的丰度和多样性的大寄生虫（Monogenea，Cestoda，Trematoda，Nematoda，Copepoda）。专性鱼类害虫的感染频率要低得多（Cestoda，Trematoda，Nematoda）。无脊椎动物共生体中专性共生体占主导地位，无脊椎动物也被弱感染。专性共生体寄生虫的丰度和多样性低，表明应在抗寄生虫防御方面进行大量投资，这与有效的防捕食防御相结合，可将专性共生体的死亡率降至最低。他们的繁殖力和人口数量通常很低。兼职共生者的死亡率可能要比专职共生者高，但是更多地使用资源和增加人口数量可以弥补这一点。兼性共生体的典型特征是感染率随宿主体大小的增加而显着增加，与专性共生体相比，它们受到的保护较小。后者在所有规模的人群中均显示出较低的感染水平。结果表明，寄生虫在塑造共生者生活策略中的作用与捕食者的作用同样重要。