Collaborative Research: Keystone chemicals: Identifying general and universal molecules of fear

许多被捕食的物种利用捕食者尿液中释放的化学物质来探测迫在眉睫的危险并做出适当的反应，但这些“恐惧分子”的身份在很大程度上仍然未知。这个提议研究了猎物是否使用相同的化学物质探测到不同的河口捕食者，或者化学信号的身份是否不同。实验的重点是常见和重要的河口猎物，泥蟹和牡蛎，以及它们的捕食者，包括鱼类、甲壳类动物和海蜗牛。从捕食者和猎物身上收集生物活性分子并对其进行表征。目的是确定猎物肉的组成或捕食者分类群与信号分子之间是否存在预测关系。了解这些信号的分子性质可以确定是否存在控制信号分子的一般规则。一旦确定，研究人员将有能力在生态学或其他类型的研究中精确地操纵或控制这些分子。牡蛎对河口健康至关重要，是重要的社会、文化和经济资源。该项目的更广泛影响包括培训来自不同背景的本科生和研究生，并与水产养殖设施和保护管理人员合作，改善牡蛎的生长和存活。对捕食者线索的一种反应包括制造更坚固的外壳来阻止捕食者。确定牡蛎用来探测捕食者的线索的身份可以提供管理选择，使牡蛎生长得更快或对捕食者更有抵抗力。项目人员正在与牡蛎养殖者合作，通过管理化学线索来提高养殖牡蛎的产量。对于海洋猎物来说，水生化学线索是关于捕食威胁的重要信息来源，因此，在许多系统中调节捕食的非消耗效应。通常这种线索是在捕食者吃掉猎物的肉时产生的。在几乎所有的情况下，负责调节这些相互作用的特定生物活性分子都是未知的，这就提出了一个问题，即是否存在一种普遍的恐惧分子，猎物会对其做出反应。因此，该项目的重点是确定河口食物网中捕食者和猎物释放的引起恐惧的代谢物的普遍性。该项目将饮食来源的尿液代谢物的代谢组学分析与生物测定相结合，以确定来自不同分类群和营养水平的两种猎物（牡蛎、泥蟹）产生反应的生物活性分子。代谢物的样本来自三种掠食者，鱼，腹足类动物或甲壳类动物。本项目旨在：1)鉴定不同分类群中几种常见的河口食肉动物产生的生物活性分子；2)比较来自捕食者的线索诱导猎物防御和猎物行为的变化；3)对比捕食者释放的线索与受伤同种动物的恐惧诱导分子的身份和效果。通过识别和对比水生分子诱导六种捕食者和受伤猎物的猎物反应的影响，该项目正在深入了解介导非致命捕食者效应的机制，同时解决与捕食者-猎物相互作用相关的长期问题。除了寻找一种普遍的恐惧分子外，实验还在探索互补和独特的化学信息在猎物对不同类型捕食者的特异性反应中的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Many prey species use chemicals released in predator urine to detect imminent danger and respond appropriately, but the identity of these ‘molecules of fear’ remains largely unknown. This proposal examines whether prey detect different estuarine predators using the same chemical or whether the identity of the chemical signals varies. Experiments focus on common and important estuarine prey, mud crabs and oysters, and their predators including fishes, crustaceans and marine snails. Bioactive molecules are being collected from predators and prey and characterized. The goal is to determine if there are predictive relationships between either the composition of prey flesh or the predator taxon and the signal molecule. Understanding the molecular nature of these cues can determine if there are general rules governing likely signal molecules. Once identified, investigators will have the ability to precisely manipulate or control these molecules in ecological or other types of studies. Oysters are critical to estuarine health, and they are important social, cultural and economic resources. Broader impacts of the project include training of undergraduate and graduate students from diverse backgrounds and working with aquaculture facilities and conservation managers to improve growth and survival of oysters. One response to predator cues involves creating stronger shells to deter predation. Determining the identity of cues used by oysters to detect predators can provide management options to produce oysters that either grow faster or are more resistant to predators. Project personnel is working with oystermen to increase yields of farmed oysters by managing chemical cues.For marine prey, waterborne chemical cues are important sources of information regarding the threat of predation, thus, modulating non-consumptive effects of predation in many systems. Often such cues are produced when the predators consume the flesh of that prey. In nearly all cases, the specific bioactive molecules responsible for modulating these interactions are unknown, raising the question whether there is a universal molecule of fear that prey respond to. Thus, the focus of the project is to determine the generality of fear-inducing metabolites released by predators and prey in estuarine food webs. The project combines metabolomics analysis of diet-derived urinary metabolites with bioassays to identify the bioactive molecules producing responses in two prey species from different taxonomic groups and trophic levels (oysters, mud crabs). Metabolites are sampled from three types of predators, fish, gastropods or crustaceans. This project aims to: 1) identify bioactive molecules produced by several common estuarine predators from different taxa; 2) compare cues from predators that induce defenses in prey vs. changes in prey behavior; and 3) contrast the identities and effects of predator-released cues with fear-inducing molecules from injured conspecifics. By identifying and contrasting the effects of waterborne molecules that induce prey responses from six predators and injured prey, this project is yielding insights into the mechanisms that mediate non-lethal predator effects, while addressing long-standing questions related to predator-prey interactions. In addition to the search of a universal molecule of fear, the experiments are exploring the role of complementary and distinct chemical information on the specificity of prey responses to different types of predators.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.