DISSERTATION RESEARCH: Feast or Flee: How do Microzooplankton Detect and Avoid Predators?

动物从捕食者和猎物那里感受到大量的触觉、嗅觉、视觉和听觉感官线索，整合这些线索，并以适当的行为做出反应;分别是回避或捕获猎物。了解动物如何整合这些多重信号以唤起复杂的行为是行为生物学的核心挑战之一。单细胞真核生物在细胞水平上具有许多与多细胞动物相同的感觉特征，因此提供了高等生物中感觉和行为特征的极好的概念和功能类似物。研究人员将使用一种海洋微型浮游动物纤毛虫，作为一种模式生物，研究感官机制，使他们能够感知和整合来自捕食者和猎物的线索，以成功捕获猎物，同时避免捕食。由于这些单细胞生物代表了真核生物的早期进化群体，因此对其感觉能力的表征将为多细胞生物中整合细胞信号传导和紧急行为特征的进化提供见解。此外，了解这些微型浮游动物（一组负责消耗约60%海洋初级生产力的生物）的捕食者-猎物相互作用，将有助于更好地了解它们在支持海洋食物网和表层海洋营养物质通量方面的作用。这两个较大的生态系统规模的过程都对海洋生态系统服务（如渔业）和影响我们气候的地球化学循环产生影响。除了这些重要的科学问题，拟议的研究将促进研究生与微型浮游动物生态学专家的跨学科合作。将促进研究人员的专业培训、科学交流和职业发展，并支持他们参加高级别的科学会议。该奖项还将允许研究人员进一步开发和实施高中学生的教学计划，这将有助于吸引他们到大学水平的科学和技术科目，并激励他们成为本科生参与研究。微型浮游动物（纤毛虫和甲藻）将大量的能量从初级生产转移到较大的后生动物消费者。这些捕食者-猎物相互作用的基础是复杂的行为，使它们能够有效地捕获首选的猎物，并通过感知和整合来自每个猎物的各种刺激来逃避捕食。尽管这些行为相互作用的生态重要性，没有以前的研究已经研究了微型浮游动物是如何能够区分捕食者和猎物，尽管从两者接收类似类型的感官信息。这项建议建立在论文研究的感觉机制，海洋微型浮游动物拥有的感觉和响应信号，从他们的猎物。第一个目的是确定Favella sp.对甲藻和桡足类捕食者的行为反应，以及这些行为反应的有效性。高速视频显微镜（250 fps）和粒子跟踪技术将量化Favella sp.的行为反应化学，机械（接触）和流体动力学刺激的捕食者和猎物。第二个目标将确定目标1中确定的捕食者行为反应的机制基础。 这将使用高速视频显微镜，电生理学和荧光离子敏感染料的组合来确定如何离子和代谢机制介导的信号转导和捕食者逃避行为。粒子图像测速仪也将被用来确定如何周围的流场Favella种。可能会被修改在捕食者逃避行为，以减少其流体动力学签名，因此，它将被摄入的可能性。总之，拟议的实验将扩展目前对纤毛虫-猎物行为相互作用的研究，以解决这种单细胞生物如何整合微尺度环境线索来检测和消耗适当的猎物，并逃避捕食者的摄入的问题。

Animals sense a multitude of tactile, olfactory, visual, and aural sensory cues from predators and prey, integrate these cues, and respond with appropriate behaviors; avoidance or prey capture, respectively. Understanding how animals integrate these multiple signals to evoke complex behaviors is one of the central challenges in the biology of behavior. Single celled eukaryotes have many of the same sensory characteristics, at the cellular level, as multicellular animals and therefore provide excellent conceptual and functional analogues of sensory and behavioral traits in higher organisms. The researcher will use a marine microzooplankton ciliate, Favella sp., as a model organism to investigate sensory mechanisms that allow them to perceive and integrate cues from predators and prey in order to successfully capture prey while avoiding predation. Because these single celled organisms represent an early evolving group of eukaryotes, characterization of their sensory capabilities will provide insights into the evolution of integrated cell signaling and emergent behavioral traits in multicellular organisms. Moreover, understanding the predator-prey interactions of these microzooplankton, a group of organisms responsible for consuming ~60 % of marine primary productivity, will enable a better understanding of the role they play in supporting marine food webs and in fluxes of nutrients in surface oceans. Both of these larger ecosystem scale processes have implications for marine ecosystem services (e.g. fisheries) and for biogeochemical cycles that impact our climate. In addition to these important science questions, the proposed research will foster cross-disciplinary collaboration of the graduate student with experts in microzooplankton ecology. Professional training, science communication and career development of the researcher will be promoted with support to attend high profile scientific meetings. The award will also allow the researcher to further develop and implement teaching programs for high school students that will help attract them to science and technology subjects at college level, and motivate them to become involved in research as undergraduates. Microzooplankton alveolates (ciliates and dinoflagellates) transfer substantial amounts of energy from primary production to larger metazoan consumers. Underlying these predator-prey interactions are complex behaviors that allow them to efficiently capture preferred prey and evade predation by sensing and integrating a variety of stimuli from each. Despite the ecological importance of these behavioral interactions, no previous research has examined how microzooplankton are able to differentiate between predators and prey despite receiving similar types of sensory information from both. This proposal builds upon dissertation research investigating the sensory mechanisms that marine microzooplankton possess to sense and respond to signals from their prey. The first objective is to determine the behavioral responses of Favella sp. to dinoflagellate and copepod predators, and the effectiveness of these behavioral responses. High-speed videomicroscopy (250 fps) and particle tracking techniques will quantify the behavioral responses of Favella sp. to chemical, mechanical (contact) and hydrodynamic stimuli from predators and prey. The second objective will determine the mechanistic basis of behavioral responses to predators identified in objective 1. This will be accomplished using a combination of high-speed video microscopy, electrophysiology, and fluorescent ion-sensitive dyes to determine how ionotropic and metabotropic mechanisms mediate signal transduction and predator evasion behaviors. Particle image velocimetry will also be utilized to determine how the flow field surrounding Favella sp. may be modified during predator evasion behaviors to decrease its hydrodynamic signature and therefore the likelihood that it will be ingested. In summary, the proposed experiments will extend current research on ciliate-prey behavioral interactions to address the question of how this single celled organism can integrate microscale environmental cues to detect and consume appropriate prey, and evade ingestion by predators.