RUI: Patterns of Prey Capture by Mnemiopsis leidyi and other Lobate Ctenophores

9820172肋瓣栉水母是海洋浮游生物群落中的重要捕食者。 主要基于以前的研究，涉及叶状属Mnemiopsis的成员，叶状栉水母通常被认为是通过消费后期（晚期桡足类和成年）桡足类影响海洋浮游生物群落。 叶状栉水母影响的定量估计依赖于结合桡足类密度和栉水母摄食率与栉水母和桡足类的实地密度之间的函数关系。 然而，晚期桡足类可能不是大多数叶状栉水母的主要猎物。 初步证据表明，拟记忆虫利用两种平行和同时的机制来捕获猎物。 第一个依赖于耳廓产生的纤毛流来夹带缓慢或不活动的猎物，这些猎物通过口触被筛选。 第二种是伏击机制，它依赖于快速游泳的猎物，如桡足类与栉水母的伸出口叶的碰撞。 一组非常有限的原位数据支持的论点，即叶状体的设计是优化的小型和弱游泳猎物和较强的游泳者，如后期桡足类是次要的营养来源，无论是从数量和生物量的角度来看。 如果后者是正确的，那么叶状栉水母的营养作用可能被普遍误解，其捕食影响大大低估。然而，这个问题的解决是目前不可能的，由于有限的信息，详细介绍了实际的猎物捕获过程和原位肠内容物的叶状栉水母。 这项研究有两个主要目标。 首先，在实验室中，对几种有代表性的裂叶栉水母类的猎物捕获的机械过程进行了适当的详细描述。 第二，定量地比较这种机械描述与这些栉水母的原位选择模式和摄食率。 需要将实验室和实地研究结合起来，以充分了解这些捕食者在海洋浮游生物群落中所起的作用。

9820172CostelloLobate ctenophores are well known as important predators in marine planktonic communities. Based primarily on previous research involving members of the lobate genus Mnemiopsis, lobate ctenophores are commonly thought to impact marine plankton communities via consumption of late stage (late copepodite and adult) copepods. Quantitative estimates of lobate ctenophore impact have relied upon combining the functional relationship between copepod density and ctenophore ingestion rate with field densities of ctenophores and copepods. However, late stage copepods may not be the primary prey of most lobate ctenophores. Preliminary evidence suggests that Mnemiopsis utilizes two parallel and simultaneous mechanisms for capturing prey. The first depends upon ciliary flow generated by the auricles to entrain slow or inactive prey which are sieved through oral tentacles. The second is an ambush mechanism which depends upon collision of rapidly swimming prey such as copepods with the ctenophore's outstretched oral lobes. A very limited group of in-situ data supports the contention that the lobate body design is optimized for feeding on small and weakly swimming prey and that stronger swimmers such as late stage copepods are a secondary nutritional source, both from a numerical and biomass perspective. If the latter is true, then the trophic role of lobate ctenophores may be commonly misunderstood and their predatory impact substantially underestimated. However, resolution of this issue is not currently possible due to the limited information available detailing the actual prey capture process and in-situ gut contents of lobate ctenophores. This research has two major goals. First, to develop an appropriately detailed description of the mechanical processes underlying prey capture in the laboratory for several representative genera of lobate ctenophores. Second, to quantitatively compare this mechanical description with in-situ selection patterns and feeding rates of these ctenophores. Both laboratory and field studies need to be integrated to fully understand the role played by these predators in marine planktonic communities.