Rohde Sven, Schupp Peter J
Carl-von-Ossietzky University Oldenburg, Institute for Chemistry and Biology of the Marine Environment (ICBM) Schleusenstr. 1, 26382 Wilhelmshaven, Germany.
J Exp Mar Biol Ecol. 2011 Mar 15;399(1):76-83. doi: 10.1016/j.jembe.2011.01.012.
Sponges have evolved a variety of chemical and structural defense mechanisms to avoid predation. While chemical defense is well established in sponges, studies on structural defense are rare and with ambiguous results. We used field and laboratory experiments to investigate predation patterns and the anti-predatory defense mechanisms of the sponge Melophlus sarasinorum, a common inhabitant of Indo-pacific coral reefs. Specifically, we aimed to investigate whether M. sarasinorum is chemically or structurally defended against predation and if the defenses are expressed differently in the ectosomal and choanosomal tissue of the sponge. Chemical defense was measured as feeding deterrence, structural defense as feeding deterrence and toughness. Our results demonstrated that chemical defense is evenly distributed throughout the sponge and works in conjunction with a structurally defended ectosome to further reduce predation levels. The choanosome of the sponge contained higher protein levels, but revealed no structural defense. We conclude that the equal distribution of chemical defenses throughout M. sarasinorum is in accordance with Optimal Defense Theory (ODT) in regards to fish predation, while structural defense supports ODT by being restricted to the surface layer which experiences the highest predation risks from mesograzers.
海绵已经进化出多种化学和结构防御机制以避免被捕食。虽然化学防御在海绵中已得到充分证实，但关于结构防御的研究却很少且结果不明确。我们通过野外和实验室实验来研究印度洋 - 太平洋珊瑚礁常见居民——沙拉西诺氏嗜海绵（Melophlus sarasinorum）的捕食模式和反捕食防御机制。具体而言，我们旨在研究沙拉西诺氏嗜海绵是通过化学方式还是结构方式抵御捕食，以及这些防御在海绵的外层体组织和领细胞层组织中表达是否不同。化学防御通过摄食威慑来衡量，结构防御通过摄食威慑和韧性来衡量。我们的结果表明，化学防御在整个海绵中均匀分布，并与具有结构防御的外层体协同作用，进一步降低捕食水平。海绵的领细胞层含有较高的蛋白质水平，但未显示出结构防御。我们得出结论，就鱼类捕食而言，沙拉西诺氏嗜海绵中化学防御的均匀分布符合最佳防御理论（ODT），而结构防御通过仅限于遭受中食草动物捕食风险最高的表层来支持最佳防御理论。
