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

[9820172] costellolobate栉水母是海洋浮游生物群落中重要的捕食者。基于先前对叶状栉水母属成员的研究，叶状栉水母通常被认为通过消耗晚期（晚期桡足动物和成年）桡足动物来影响海洋浮游生物群落。对栉水母影响的定量估计依赖于将桡足动物密度和栉水母摄食率之间的函数关系与栉水母和桡足动物的野外密度相结合。然而，晚期桡足类动物可能不是大多数裂片栉水母的主要猎物。初步证据表明，记忆opsis利用两种平行和同时的机制来捕获猎物。第一种依赖于耳廓产生的纤毛流，通过口触须过滤缓慢或不活动的猎物。第二种是伏击机制，它依赖于快速游动的猎物（如桡足类动物）与栉水母伸出的口垂的碰撞。一组非常有限的原位数据支持这样一种观点，即叶状体的设计是为捕食小型和弱游动的猎物而优化的，而从数值和生物量的角度来看，较强的游动者（如晚期桡足类）是次要营养来源。如果后者是正确的，那么叶状栉水母的营养作用可能通常被误解，它们的掠食性影响可能被大大低估。然而，由于详细描述叶状栉水母的实际猎物捕获过程和原位肠道内容物的信息有限，目前不可能解决这个问题。这项研究有两个主要目标。首先，对几个有代表性的叶状栉水母属在实验室中捕获猎物的机械过程进行适当详细的描述。其次，将这种力学描述与这些栉水母的原位选择模式和摄食速率进行定量比较。实验室和实地研究需要结合起来，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.