Fucoid inducible defenses: the causes and consequences of intraspecific variation

许多猎物物种在形态和化学等特征上表现出可诱导的变化，以响应消费者的需求。这种诱导防御被认为是适应性的，因为它们降低了反应物种对消费的脆弱性。尽管我们欣赏诱导防御在分类学上的普遍存在，但我们对诱导防御在物种内的变异知之甚少。这是有问题的，因为涉及同一捕食者物种对的相互作用往往发生在广泛的地理范围内，这些相互作用的动态可能在很大程度上取决于当地的环境背景。如果我们要更好地理解诱导防御在构建自然群落中所起的作用，对这个问题的关注是至关重要的。本项目研究了两种海藻(节瘤海藻和泡囊海藻)对两种草食蜗牛(Littorina littorea和Littorina obtusata)捕食线索的反应中诱导防御的大规模变化，这两种蜗牛在缅因湾多岩石的潮间带海岸很常见。这两种海藻在退潮时为潮间带群落提供了基本的热缓冲，它们的主要消费者在岩石海岸群落动态中发挥着关键作用。因此，通过专注于这些海藻-草食动物的相互作用，研究人员希望对诱导防御在构建岩石海岸群落中所起的作用以及这种作用如何在地理上有所不同有相当的了解。事实上，他们之前对缅因湾海藻种群的研究以及其他人对欧洲种群的研究表明，这些海藻表现出诱导防御的能力存在相当大的差异。这个项目将结合实验室和现场的方法来解决以下问题：1.海藻对草食动物的诱导防御是否表现出地理差异？2.海藻诱导防御的程度是否与总体放牧强度或放牧变化有关？3.海藻诱导防御的成本和收益是如何由草食动物的耐受性决定的？这项研究将通过探索海藻-食草动物相互作用的性质，在异常广泛的空间尺度上，对群落生态学和可诱导防御的进化生态学做出重大的新的智力贡献。该项目将显著增加本科生和初中生的研究和教育机会。研究生将直接参与这项研究的所有方面，包括实验维护、数据分析和手稿开发。主要研究人员将继续坚定地致力于本科教育，让本科生(通过三洋计划)协助执行我们的实验。该项目还将通过与海洋科学中心的外联计划互动，让初中生参与研究。这项计划的目标是波士顿公立学校，那里的大多数学生来自代表人数不足的群体。在与外联计划的合作下，调查人员将设计符合马萨诸塞州生命科学标准的新课程计划。通过制定具有外展功能的教案，调查人员有能力教育广泛和多样化的学生群体。与外展学生的互动将进一步提高他们对海洋科学的热情，以及MSC外展计划提供的教学和研究经验。

Numerous prey species exhibit inducible changes in traits such as morphology and chemistry in response to consumers. Such inducible defenses are thought to be adaptive because they reduce the vulnerability of the responding species to consumption. Although we appreciate the taxonomic ubiquity of inducible defenses, we have a poor sense of the variation in inducible defenses within a species. This is problematic because interactions involving the same prey-consumer species pair often occur over broad geographic ranges and the dynamics of these interactions may strongly depend on the local environmental context. Attention to this issue is critical if we are to better understand the role that inducible defenses play in structuring natural communities. This project examines large-scale variation in the inducible defenses of two seaweeds (Ascophyllum nodosum, Fucus vesiculosus) in response to grazer cues from two herbivorous snails (Littorina littorea, Littorina obtusata) that are common on the rocky intertidal shores of the Gulf of Maine. Both seaweeds provide essential thermal buffering for the intertidal community during low tides and both of their primary consumers play a key role in rocky shore community dynamics. Hence, by focusing on these seaweed-herbivore interactions, the investigators expect to obtain considerable insight into the role that inducible defenses have in structuring rocky shore communities and how this role may vary geographically. Indeed, their previous work with Gulf of Maine seaweed populations, and that of others on European populations, suggests that there are considerable differences in the capacity of these seaweeds to exhibit inducible defenses. This project will combine laboratory and field approaches to address the following questions: 1. Do seaweeds display geographic variation in inducible defenses in response to herbivores? 2. Does the degree of seaweed inducible defense correlate with overall grazing intensity or grazing variability? 3. How are the costs and benefits of seaweed inducible defenses shaped by herbivore tolerance? The research will make significant novel intellectual contributions to community ecology and the evolutionary ecology of inducible defenses by exploring the nature of seaweed-herbivore interactions across an unusually broad spatial scale. This project will significantly enhance the research and educational opportunities of undergraduate, and junior high school students. Graduate students will participate directly in all aspects of this research, including experimental maintenance, data analysis, and manuscript development. The principal investigators will continue a strong commitment to undergraduate education by having undergraduate students (via the Three Seas Program assist with the execution of our experiments. The project will also involve junior high students in the research by interacting with the Marine Science Center's Outreach Program. This program targets Boston Public Schools where the majority of students are from under-represented groups. In collaboration with the Outreach Program, the investigators will design new lesson plans that align with the Massachusetts Life Science Standards. By developing lesson plans with outreach, the investigators have the ability to educate a broad and diverse group of students. Interactions with Outreach students will further enhance their enthusiasm for marine science as well as the teaching and research experience offered by the MSC's Outreach Program.