Collaborative Research: The Effects of Flow on the Nature and Strength of Indirect Effects

营养级联的经典观点强调捕食者对其猎物的消耗效应和新兴的间接捕食者对基础资源的影响（密度介导的间接相互作用，DMIIs）。然而，越来越清楚的是，非消耗性捕食者对猎物性状的影响也可能导致对低营养水平的强大间接影响（性状介导的间接相互作用，TMIIs）。这种性状介导的级联反应在水生系统中很常见，因为猎物对水生化学信号的反应显示出反捕食者的行为，从而增加了被捕食的风险。这些化学物质通过流动的水在捕食者和猎物之间运输，因此受到流体动力（例如湍流）的影响，可以改变化学信号结构和捕食者-猎物物种对的化学接受能力。因此，湍流对化学接受的影响可能会强烈影响dmii和tmii的相对重要性，这取决于这种影响如何影响捕食者寻找猎物的能力和猎物避免被吃掉的能力。本研究的主要目的是研究流动对捕食者和猎物感官能力的影响如何影响间接影响的性质和强度。Drs。Smee和Trussell将通过实验室和实地实验来探讨这个问题，在一个三营养的潮间带岩石食物链上进行实验，该食物链包括食肉绿蟹（Carcinus maenas），中间消费者（食肉蜗牛，Nucella lapillus），以及蜗牛的主要食物资源之一（藤壶，Semibalanus balanoides）。先前的研究表明，dmii和tmii都可以在这个食物链中起作用，并且从其他系统中有很好的证据表明，水动力制度可以强烈影响螃蟹捕食者及其猎物的化学接受能力。以下问题是这个项目的核心：水动力如何影响青蟹对风险提示的反应？水动力如何影响绿蟹的觅食行为和成功？水动力如何塑造田间营养级联的性质和强度？研究结果将在水动力机制对捕食者-猎物化学信号的影响和间接捕食者效应之间提供新的联系，间接捕食者效应通常在自然群落结构中起关键作用。该研究项目将为3名研究生、1名博士后和数名本科生提供培训。德克萨斯农工大学、科珀斯克里斯蒂大学（TAMUCC）和东北大学参与了这个合作项目。学生将体验到丰富的跨学科研究环境，融合了化学生态学，流体动力学和社区生态学的专业知识。

Classical views of trophic cascades emphasize the consumptive effects of predators on their prey and emergent indirect predator effects on basal resources (density-mediated indirect interactions, DMIIs). However, it is increasingly clear that non-consumptive predator effects on prey traits can also lead to powerful indirect effects on lower trophic levels (trait-mediated indirect interactions, TMIIs). Such trait-mediated cascades are quite common in aquatic systems and emerge because prey exhibit anti-predator behaviors in response to waterborne chemical cues signaling increased predation risk. These chemicals are transported between predators and prey by flowing water and are thus subject to hydrodynamic forces (e.g. turbulence) that can alter chemical signal structure and the chemoreceptive abilities of a predator-prey species pair. Hence, the effects of turbulence on chemoreception may strongly influence the relative importance of DMIIs and TMIIs depending on how such effects influence the ability of predators to find prey and the ability of prey to avoid being consumed. The primary goal of this research is to examine how flow effects on the sensory capabilities of both predators and prey influence the nature and strength of indirect effects. Drs. Smee and Trussell will explore this issue with laboratory and field experiments on a tri-trophic, rocky inter-tidal food chain containing the predatory green crab (Carcinus maenas), an intermediate consumer (the carnivorous snail, Nucella lapillus), and one of this snail's principal food resources (the barnacle, Semibalanus balanoides). Previous work has shown that both DMIIs and TMIIs can operate within this food chain and there is good evidence from other systems that hydrodynamic regime can strongly influence the chemoreceptive abilities of crab predators and their prey. The following questions are central to the project:1. How do hydrodynamic forces influence the responses of Nucella to green crab risk cues?2. How do hydrodynamic forces influence green crab foraging behavior and success?3. How do hydrodynamic forces shape the nature and strength of trophic cascades in the field? The results of the research will provide a novel link between the effects of hydrodynamic regime on predator-prey chemical signaling and indirect predator effects that often play a pivotal role in the structuring of natural communities. The research project will provide training for three graduate students, one postdoctoral fellow, and several undergraduate students. in the collaborative project involving Texas A&M, Corpus Christi (TAMUCC) and Northeastern University. Students will experience a rich interdisciplinary research environment that blends expertise in chemical ecology, hydrodynamics, and community ecology.