Predator-induced morphological defenses of marine zooplankton

智力价值--捕食者诱导的猎物防御结构的变化发生在不同的有机体和栖息地。奇怪的是，对参考数据库的搜索没有发现海洋浮游动物发生这种变化的报道。相比之下，关于淡水浮游动物、底栖海洋动物和浮游植物由捕食者引起的形态变化的报道很多。PI实验室的实验已经证明，捕食者会导致浮游绒毛虫外壳的变化，笼子里的捕食者会在没有直接接触的情况下诱导这种变化，而这种事先接触到捕食者的行为随后会降低绒毛虫的脆弱性。这项研究将这些研究扩展到各种海洋浮游动物。研究集中在四个捕食者-捕食者之间的相互作用：腹足丝虫为猎物，蟹类为捕食者；棘足类、蟹类、无节幼体和桡足类为猎物，鱼类为捕食者。对于每一种捕食者-捕食者组合，需要检验的假设是(1)假定的防御结构对来自捕食者、受伤的同种猎物的刺激的反应不同，以及(2)事先暴露于捕食者降低了脆弱性。如果这些结果是肯定的，那么将检验另外两个假设。(3)暴露于捕食者后脆弱性的降低涉及诱导的防御形态(如直接观察捕食者的攻击和对暴露于捕食者和捕食者未成熟的猎物的处理以及猎物的逃逸)。(4)暴露引起猎物形态的变化会导致猎物生长缓慢。如果假设1的结果对于一个猎物物种是否定的，那么将测试其他种类的猎物和捕食者。诱导的形态防御传达了关于野外捕食者-猎物相互作用的信息，捕食风险的变化，降低死亡率和降低死亡率差异的过程，有效防御捕食者的特征，以及防御的权衡。此外，如果诱导防御很常见，忽视防御及其权衡将导致错误设计的实验室实验和对数据的误解。或者，如果捕食者诱导的防御在海洋浮游动物中被证明是罕见的，那么海洋浮游动物的风险和防御的成本和收益与淡水浮游动物的不同。广泛影响--该项目包括研究生论文研究，并支持本科生的研究。这项研究将让一名本科生参加星期五港湾实验室(FHL)的一个项目，该项目得到Blinks奖学金的支持，该项目旨在让代表人数较少的少数族裔的学生参与海洋科学的研究。与PI合作指导本科生研究将提高研究生作为教师的经验。国际和平协会和学生还将在FHL面向公众的讲座和开放日以及国内和国际会议上介绍成果。PI将把这项研究的结果和新问题纳入到幼虫生态学的课程中。来自国内和国际许多机构的学生在FHL学习这门课程。海洋浮游动物生活在地球上最大的栖息地，遇到不同种类的捕食者，形态诱导防御的频率或稀缺性将进一步引发关于刺激的特异性和反应有效性的问题，并提供与淡水浮游动物的信息对比。

Intellectual Merit -- Predator-induced changes in the defensive structures of prey occur in diverse organisms and habitats. Curiously, a search of reference data bases reveals no reports of such changes for marine zooplankton. In contrast, reports of predator-induced morphological changes are numerous for freshwater zooplankton, benthic marine animals, and phytoplankton. Experiments in the PI's lab have demonstrated that predators induce changes in shells of the planktonic veligers, that caged predators induce the change without direct contact, and that this prior exposure to a predator subsequently decreases vulnerability of the veligers. This research extends these studies to diverse kinds of marine planktonic animals. The study concentrates on four prey-predator interactions: gastropod veligers as prey with crab zoeas as predators; echinoid plutei, crab zoeas, and copepod nauplii and copepodids as prey with fish as predators. For each prey-predator combination, the hypotheses to be tested are (1) presumed defensive structures develop differently in response to stimuli from predators, injured conspecific prey, and (2) prior exposure to predators reduces vulnerability. If these results are positive, two other hypotheses will be tested. (3) The reduced vulnerability following exposure to predators involves the induced defensive morphology (as indicated by direct observations of predators' attacks and handling of predator-exposed and predatornaive prey and the escapes by prey). (4) Exposure that induces changes in prey morphology results in slower prey growth. If results for hypothesis 1 are negative for a prey species, additional kinds of prey and predators will be tested. Induced morphological defenses convey information about predator-prey interactions in the field, variation in predation risk, processes that reduce mortality and reduce variation in mortality, what features are effective defenses against predators, and trade-offs for defenses. Also, if induced defenses are common, ignoring the defenses and their trade-offs will result in incorrectly designed laboratory experiments and misinterpretation of data. Alternatively, if predator-induced defenses prove to be rare among marine planktonic animals, then the risks for marine zooplankton and the costs and benefits of defenses differ from those for freshwater zooplankton.Broader Impacts -- The project includes a graduate student's dissertation research and supports research by undergraduates. The research will involve an undergraduate supported by a Blinks Fellowship, in a program at the Friday Harbor Laboratories (FHL) that is designed to bring students in underrepresented minorities into research in the marine sciences. Mentoring of undergraduate research jointly with the PI will enhance the graduate student's experience as a teacher. The PI and students will also present results in the lectures and open houses at FHL for the general public and at national and international meetings. The PI will incorporate result and new questions from this research into courses in larval ecology. Students from many institutions nationally and internationally take this course at FHL. The frequency or scarcity of morphological induced defenses will raise further questions about the specificity of stimuli and effectiveness of responses in marine zooplankton, which live in the largest habitat on earth, encounter diverse kinds of predators, and provide informative contrasts with freshwater zooplankton.