Chemosensory Mechanisms Regulating Predation

调节捕食的化学感应机制

• 批准号: 9729980
• 负责人: Richard Zimmer
• 金额: $ 26.97万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-01 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9729980&HistoricalAwards=false
• 关键词: Chemosensory; Mechanisms; Regulating; Predation

Predation is a major biotic force regulating prey populations, as well as exerting strong effects on community structure. Evidence suggests that the sense of smell mediates predatory search in many terrestrial and aquatic animals. Past investigations have not, however, been designed to link either the degree of successful olfactory-mediated search or guidance mechanisms with the production of chemical attractant by prey or the hydraulic environment in which predatory activities naturally take place. Using the predator - prey interaction between blue crabs (Callinectes sapidus) and hard clams (Mercenaria mercenaria), this project will investigate the olfactory basis for predation. Results from assays of crab predatory search behavior will guide chemical fractionation and isolation of peptide attractants being released by intact live clams. Water collected from the excurrent siphons of actively pumping clams will be characterized by partitioning into different molecular weight classes and by using selective enzyme degradation to probe peptide structures. As attractants are isolated and identified, pure compounds will be bioassayed for potency (dose-response) and for potential mixture interactions. In this manner, the natural ligands will be discovered and made available for discriminating between the roles of antennules and legs in chemosensation that mediates crab predatory search behavior. The rates of water exchange and attractant flux will then be measured for clams, and a biomechanical and chemical model of a clam releasing attractants will be engineered. Crab ability to find clam patches will be tested under controlled hydrodynamic conditions in a large (10-m long) flume, simulating flow in the natural habitat. As a final test, selected experiments will be repeated in the field by using live clams and models as attractant sources to free-ranging crabs. This project will thus provide the most rigorous test to date of olfaction as a regulatory factor in predator-prey interactions. It will yield new attractant structures for use in cellular and molecular studies on basic chemosensory processes, while it will provide a critical link between the olfactory sense of predators and prey vulnerability to predation. Finally, it could open significant avenues for future research to explore the mechanisms through which prey might defend themselves by adopting risk-sensitive metabolic strategies in which attractant production stops when nearby predator are detected.

捕食是调节猎物种群数量的主要生物力量，对群落结构有着重要的影响。 有证据表明，嗅觉在许多陆生和水生动物中介导捕食性搜索。 然而，过去的调查并没有被设计成将成功的嗅觉介导的搜索或指导机制的程度与猎物或捕食活动自然发生的水力环境中的化学引诱剂的生产联系起来。 本计画将利用青蟹与蛤蚌之间的捕食-被捕食关系，探讨捕食的嗅觉基础。 蟹类捕食性搜索行为的测定结果将指导完整活蛤释放的肽引诱剂的化学分馏和分离。 从主动泵送蛤的流出虹吸管收集的水将通过划分为不同的分子量类别和通过使用选择性酶降解来探测肽结构来表征。 当引诱剂被分离和鉴定时，将对纯化合物的效价（剂量-反应）和潜在的混合物相互作用进行生物测定。 以这种方式，天然配体将被发现，并可用于区分触角和腿在介导螃蟹捕食搜索行为的化学感觉中的作用。 水交换率和引诱剂流量，然后将测量蛤，蛤释放引诱剂的生物力学和化学模型将工程。 螃蟹找到蛤蜊补丁的能力将在一个大的（10米长）水槽中进行测试，模拟自然栖息地的流动。 作为最后一项试验，将在实地重复选定的实验，使用活蛤和模型作为对自由放养的螃蟹的引诱剂来源。 因此，该项目将提供最严格的测试嗅觉作为捕食者-猎物相互作用的调节因素。 它将产生新的引诱剂结构用于细胞和分子研究的基本化学感受过程，而它将提供一个关键的捕食者和猎物的嗅觉之间的联系脆弱性捕食。 最后，它可以为未来的研究开辟重要的途径，探索通过采取风险敏感的代谢策略，其中引诱剂的生产停止时，附近的捕食者被检测到猎物可能会保护自己的机制。