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

许多猎物物种使用捕食者尿液中释放的化学物质来检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不清楚。这一建议检查了猎物是否检测到使用相同化学物质的不同河口捕食者，或者化学信号的身份是否有所不同。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、甲壳类和海洋蜗牛。生物活性分子正在从捕食者和猎物中收集并进行表征。目标是确定在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管理可能的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操纵或控制这些分子。牡蛎对河口的健康至关重要，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经理合作，以改善牡蛎的生长和存活。对捕食者暗示的一种反应是创造更坚固的贝壳来阻止捕食。确定牡蛎用来检测捕食者的线索的身份，可以为生产出生长更快或对捕食者更具抵抗力的牡蛎提供管理选择。项目人员正在与牡蛎人合作，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，水中化学线索是有关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性影响。通常，当捕食者吃掉猎物的肉时，就会产生这样的线索。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，这引发了一个问题，即是否存在一种普遍存在的恐惧分子，猎物对此做出反应。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。该项目将对饮食衍生的尿代谢物的代谢组学分析与生物测定相结合，以确定在来自不同分类群和营养水平(牡蛎、蟹)的两个猎物物种中产生反应的生物活性分子。代谢物来自三种类型的捕食者，鱼、腹足类或甲壳类。这个项目的目的是：1)识别来自不同分类群的几种常见河口捕食者产生的生物活性分子；2)比较来自捕食者诱导猎物防御的线索与猎物行为的变化；以及3)比较捕食者释放的线索与来自受伤同种生物的恐惧诱导分子的身份和效果。通过识别和对比六种捕食者和受伤猎物的水基分子对猎物反应的影响，该项目正在深入了解调节非致命性捕食者效应的机制，同时解决与捕食者-猎物相互作用有关的长期存在的问题。除了寻找一种通用的恐惧分子外，这些实验还在探索补充和独特的化学信息在不同类型捕食者对猎物反应的特殊性上的作用。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.