Zooplankton Photoresponses during Diel Vertical Migration: Modificaiton by Chemical Cues from Predators

大多数浮游动物经历昼夜垂直迁移（DVM）， 发展阶段。常见的模式包括一个上升近 日落和下降接近日出。 最普遍的功能 对此的解释是，动物在夜间起来觅食， 白天避开视觉导向的捕食者。 最近的研究 表明存在和不存在食虫动物可以改变DVM 通过快速的行为变化。因为光是最重要的 DVM的线索，由捕食者的线索改变迁移应该 涉及光反应的变化。 因此，光响应可以是 用作行为测定以指导表征、纯化 和识别来自捕食者的化学线索。 的 该项目的目标是：（1）确定是否 DVM中涉及的光反应被存在或 没有食鱼动物做（鱼）和不（栉水母和 chaetognath）视觉上看到他们的猎物，（2）以确定是否 来自捕食者的化学线索引起浮游动物的变化 参与DVM的光响应，以及（3）表征 捕食者的化学信号 哈氏扇头蟹和盐水虾的幼虫 （卤虫属）将进行研究，因为两者都接受了DVM， 初步研究表明，它们的光反应被改变， 食草动物的化学线索 将监测光反应 与视频系统，并在一个装置，模仿测试 自然水下角光分布。 初步研究 表明鱼类的活性化学物质小于500道尔顿 研究人员预测， 生物活性分子是通过水解产生的气味， 常见于鱼类表面的分子。 二糖 来源于鱼粘液的小肽， 上皮蛋白是可能的候选者。

Most zooplankton undergo diel vertical migration (DVM) at some stage of development. The common pattern involves an ascent near sunset and descent near sunrise. The most pervasive functional explanations are that animals rise to feed at night and descend to avoid visually-oriented predators during the day. Recent studies indicate the presence and absence of planktivores can alter DVM through rapid behavioral changes. Since light is the most important cue for DVM, alterations in migration by cues from predators should involve changes in photoresponses. Thus, photoresponses can be used as a behavioral assay to direct characterization, purification and identification of the chemical cue(s) from predators. The objectives of this project are: (1) to determine whether photoresponses involved in DVM are altered by the presence or absence of planktivores that do (fish) and do not (ctenophore and chaetognath) visually sight their prey, (2) to determine whether chemical cues form predators induce alterations in zooplankton photoresponses that are involved in DVM, and (3) to characterize the chemical cues form the predators. Larvae of the crab Rhithropanopeus harrisii and of brine shrimp (Artemia sp.) will be studied because both undergo DVM and preliminary studies suggest their photoresponses are altered by chemical cues from planktivores. Photoresponses will be monitored with a video system and tested in an apparatus that mimics the natural underwater angular light distribution. Preliminary studies indicate the active chemicals from fish are less than 500 Daltons in molecular size and the investigators predict that the biologically active molecules are odors generated by hydrolysis of molecules found commonly on fish surfaces. Disaccharides originating form fish mucus, and small peptides originating from epithelial proteins are likely candidates.