Collaborative Research: Anti-Predator Defenses of Marine Hydroids: Alternative Strategies, Biogeographic Patterns, and Ecological Implications

合作研究：海洋水螅的反捕食者防御：替代策略、生物地理模式和生态影响

• 批准号: 0082049
• 负责人: John Stachowicz
• 金额: $ 21.99万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0082049&HistoricalAwards=false
• 关键词: Collaborative; Research; Anti; Predator; Defenses

Optimality theory suggests that preferential allocation of resources to one form of defense should occur among a series of alternative defenses resulting in a single prevailing defense strategy. Although this idea has been widely accepted, few studies provide rigorous evidence to support the notion of trade-offs among defense systems, particularly in marine systems. The PI's recent data indicate that, with stinging organelles (nematocysts) and secondary metabolites as likely alternative defenses (Stachowicz & Lindquist 1997, in press), marine hydroids may provide an excellent system with which to test optimality theory and its implications for the evolution of defensive strategies among marine organisms. Using proven experimental methodologies to distinguish between nematocyst-defended and chemically-defended hydroids, The investigators will rigorously test the hypothesis that defensive nematocysts and secondary metabolites do not co-occur in marine hydroids and thus represent alternative defensive strategies. They will also test a second hypothesis that hydroids are not also defended by low nutritional value by examining correlations among whole polyp palatability, nematocyst types, chemical palatability, and nutritional parameters. Where chemical defenses are apparent, they will isolate and structurally characterize deterrent metabolites so that they can examine secondary biosynthetic diversity among hydroids relative to their phylogeny, patterns and scales of intraspecific chemical variability, compound localization, and elemental composition as they relate to hydroid anti-predator strategies and potential costs of the chemical defense.In addition the PIs will conduct a separate set of field and laboratory studies examining the ecological implications of altemative anti-predator defenses for other trophic levels. Specifically, they will test the hypothesis that epifauna abundance and diversity will be lower among nematocyst defended hydroids than among chemically defended hydroids because stinging nematocysts can harm associated epifauna. Because hydroids form the "foundation" on which an entire epifaunal community depends, negative effects of some hydroid defenses on epifauna could have important consequences for community composition and the function of these ecosystems. They will test these hypotheses on 3 different hydroid faunas: (1) the temperate Atlantic (NC); (2) the Caribbean (FL); and (3) the temperate (but less seasonal) eastern Pacific (northern CA), allowing biogeographic comparisons of hydroid defenses against predators. The results of this study will provide a conceptual framework for comparing ecological and evolutionary consequences of chemical vs. nematocyst defenses among broader groups of cnidarians that presently seem to rely largely on chemical defenses (e.g., octocorals like gorgonians and soft corals) vs. those such as sea anemones and hard corals that seem to rely on nematocysts for defense.

最佳理论表明，在一系列替代防御措施中，应优先分配资源为一种防御形式，从而产生单一的普遍防御策略。 尽管这个想法已被广泛接受，但很少有研究提供严格的证据来支持国防系统（特别是海洋系统中）之间权衡的概念。 PI的最新数据表明，随着刺痛器（线虫囊）和次级代谢产物的可能性替代防御（Stachowicz＆Lindquist 1997，印刷中），海洋水力体可能会提供一个极好的系统，可提供一个极好的系统，以测试最优化理论及其对海洋机构中防守策略进化的影响。 使用经过验证的实验方法来区分黑局防御和化学预防的水型，研究人员将严格检验以下假设：防御性线虫和二级代谢物在海洋水力体中不同时发生，因此代表了替代的防御策略。 他们还将检验第二个假设，即通过检查整个息肉性古质性，线虫类型，化学可古素性和营养参数之间的相关性，也没有通过低营养价值来捍卫水。 如果化学防御明显，它们将在结构上隔离和结构表征威慑代谢物，以便他们可以检查氢化物之间的二级生物合成多样性相对于它们的系统发育，种内化学可变性的模式和尺度，化学变异性，化合物定位，复合本地定位，以及元素的组成，与型号的策略辩护相关。研究其他营养水平的高度抗侵犯防御能力的生态意义。 具体而言，他们将检验以下假设：在卫生部防御型氢化剂中，表现丰度和多样性将低于化学捍卫的水力，因为刺痛的线虫可能会损害相关的epifauna。 由于水力体构成了整个Epifaunal社区的“基础”，因此某些水力防御对Epifauna的负面影响可能会对社区组成和这些生态系统的功能产生重要影响。 他们将在3种不同的氢化动物动物群上检验这些假设：（1）温带大西洋（NC）； （2）加勒比海（FL）； （3）温带（但季节性）东太平洋（北部CA），从而可以比较对捕食者的水力学防御措施。 The results of this study will provide a conceptual framework for comparing ecological and evolutionary consequences of chemical vs. nematocyst defenses among broader groups of cnidarians that presently seem to rely largely on chemical defenses (e.g., octocorals like gorgonians and soft corals) vs. those such as sea anemones and hard corals that seem to rely on nematocysts for defense.