The effect of epibionts on the susceptibility of the red seaweed Cryptonemia seminervis to herbivory and fouling
The effect of epibionts on the susceptibility of the red seaweed Cryptonemia seminervis to herbivory and fouling
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DOI：
10.1080/08927010802041253
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发表时间：
2008-01-01
期刊：
影响因子：
2.7
通讯作者：
Pereira, Renato C.
中科院分区：
文献类型：
--
作者：
da Gama, Bernardo A. P.;Santos, Rodrigo P. de A.;Pereira, Renato C.
附着或污染对生物体有直接和间接的有害影响，特别是对光合生物，如海藻。因此，假设大型藻类被选择存在或诱导防污（AF）防御似乎是合理的。红海藻隐藻（Cryptonemia seminervis）通常是在自然界中发现的，具有较高的表层生物覆盖。为了评估外生作用对这种海藻对草食和污染的敏感性的影响，我们评估了污染的丰度，并将其与污染的（苔藓虫和海绵）和未污染的C. seminervis的草食消耗（由片脚类和海胆）进行了比较。用海藻提取物处理过的贻贝附着在表面上的情况也进行了评估。表皮寄生约占半蜜藤叶片表面的51%，有时覆盖高达90%至51%的菌体重量，主要包括苔藓虫膜孔虫和一种未知的海绵。与没有外生生物的藻类相比，被膜藻定植的藻类更受青睐，这是一种“共享厄运”效应，无论是对片足类动物Elasmopus brasiliensis还是对海胆Lytechinus variegatus （p < 0.01）。海绵表层生物也增加了这两种食草动物的食用量（p < 0.001），这表明表层生物可能对食草动物起到了诱饵的作用，吸引了否则不会以海藻为食的消费者。海胆更喜欢含有被污染的褐藻提取物的食物，而不是没有表观生成物的藻类。然而，与无表面生物的藻类相比，污染藻类的提取物抑制贻贝附着。差异可能是表生菌存在的直接有害影响。另一方面，表皮生长也可能诱导黄貂鱼AF防御的产生。
Epibiosis or fouling on living organisms can have direct and indirect detrimental effects, in particular on photosynthetic organisms such as seaweeds. It thus seems reasonable to hypothesize that macroalgae have been selected for the presence or induction of antifouling (AF) defences. The red seaweed Cryptonemia seminervis is usually found in nature with an elevated cover of epibionts. To assess the effect of epibiosis on the susceptibility of this seaweed to herbivory and fouling, the abundance of fouling was evaluated and compared to herbivore consumption (by amphipods and sea urchins) of fouled (bryozoan and sponge) and non-fouled C. seminervis. Attachment of the mussel Perna perna to surfaces treated with extracts from seaweeds with and without epibionts was also assessed. Epibiosis corresponded to ca. 51% of the blade surface of C. seminervis, sometimes covering as much as 90% and up to 51% of the thallus weight, encompassing mainly the bryozoan Membranipora membranacea and an unidentifiied sponge. Algae colonized by M. membranacea were preferred compared to algae devoid of epibionts, a 'shared doom' effect, either by the amphipod Elasmopus brasiliensis or by the urchin Lytechinus variegatus (p < 0.01). Sponge epibiosis also increased consumption by both herbivores (p < 0.001), suggesting that epibionts may act as lures to herbivores, attracting consumers that otherwise would not feed significantly on the seaweed. Foods containing extracts from fouled C. seminervis were preferred by urchins over the alga devoid of epibionts. However, extracts from fouled alga inhibited mussel attachment when compared to epibiont-free alga. Differences might be a direct detrimental effect of the presence of epibionts. On the other hand, epibiosis may induce the production of AF defences in C. seminervis.