Biomechanics of suction feeding in teleost fishes

硬骨鱼吸食的生物力学加州大学戴维斯分校peter wainwright这项研究将调查水生吸食的流体力学，这是脊椎动物中最常用的捕食方法。吸食在每一种主要陆生脊椎动物的水生物种中都有发现，也是硬骨鱼类使用的主要捕食机制，硬骨鱼类占所有脊椎动物物种的一半以上。这种行为包括嘴和口腔的爆炸性扩张，以加速水和猎物进入口中。吸力流对猎物施加力，将它们运送到捕食者那里，这些流决定了吸力捕食者的成功。由于观察高速水流运动的技术挑战，对吸力进料流的直接观察很少。该项目的目的是利用新技术研究这些水流模式，并研究捕食者和猎物相互作用的机制。通过提供关于动物如何操纵它们所生活的水来捕获食物的基本知识，这项研究将有助于我们理解脊椎动物进化的一个主要时期，并将加深我们对硬骨鱼头骨设计与喂养生态学和进化之间关系的见解。将进一步开发数学计算流体动力学模型，并结合数字粒子图像测速（DPIV）的实验流动可视化来表征吸力流动的时空分布及其对吸力进料性能的影响。DPIV使用宽约5厘米、厚约2毫米的激光片来照射水中的中性浮力粒子。高速视频（500 - 1000图像/秒）是直接在这个光片和水的运动是通过跟踪悬浮在水中的粒子可视化。计算机程序通过分析粒子运动的连续视频图像来精确地推断水的速度模式。在吸力喂食（称为“公羊喂食”）过程中，向前游动行为对由吸力产生的水流模式的影响将被测量。此外，吸力流对猎物施加的力将通过水流模式的推断和直接使用力传感器来测试加速反应的假设来测量，加速反应是一种以前被忽略的由速度变化的水流产生的力，超过了猎物在水流中所经历的更熟悉的阻力。加速反应的一个重要作用可能会极大地改变猎物所经历的力的图像，并可能有助于解释吸力进食的爆炸性，它可以在不到10毫秒的时间内发生，这是脊椎动物中最快的进食行为之一。该项目的第二部分将旨在了解不同鱼类吸食性能的差异。本研究将研究淡水鱼Centrarchidae科中的四个物种，它们代表了该科中已知的吸食能力的范围。此外，还将研究具有相似生态形态多样性的慈鲷科四种平行序列。将使用DPIV测量每个物种的吸吸流量峰值，同时使用超声方法测量口腔和口腔扩张，该方法可以精确量化喂食过程中口腔内部尺寸的变化。本项目的更广泛影响可能涉及应用非定常流动的信息，以在外科吸引装置的开发中增强对目标体施加的力。这项研究将为一名博士后研究员、一名女研究生和一名来自代表性不足群体的本科生提供培训。博士后将获得教学经验，研究生将设计一个关于水生动物摄食的实验练习，用于脊椎动物进化课程。将开发一个网站，提供有关吸食的信息和喂鱼的电影片段，供大学教师在有机体生物学课程中使用。

Biomechanics of Suction Feeding in Teleost FishesPeter WainwrightUniversity of California, DavisThis research will investigate the fluid mechanics of aquatic suction feeding, the most commonly used method of prey capture among vertebrate animals. Suction feeding is found in aquatic species of every major group of land-dwelling vertebrates, and is the principal prey-capture mechanism used by bony fishes, a group that makes up over half of all vertebrate species. This behavior involves the explosive expansion of the mouth and oral cavity to accelerate water and prey into the mouth. Suction flows exert forces on prey, transporting them to the predator, and these flows determine the success of suction feeders. Because of the technical challenges associated with observing high-speed water motion, very few direct observations of suction feeding flows have been made. The purpose of this project is to study these water flow patterns using new technologies and to study the mechanics of predator prey interactions. By contributing basic knowledge about how animals manipulate the water they live in to capture food this research will contribute to our understanding of a major period in vertebrate evolution and will deepen our insight into the relationship between skull design and feeding ecology and evolution in teleost fishes. A mathematical computational fluid dynamic model will be further developed and used in conjunction with experimental flow visualization by Digital Particle Image Velocimetry (DPIV) to characterize the temporal and spatial distribution of suction flows and how they influence suction feeding performance. DPIV uses a laser light sheet about 5 cm in width and 2 mm thick to illuminate neutrally buoyant particles in the water. High speed video (500 - 1000 images/s) is directed at this light sheet and water motion is visualized by tracking the particles suspended in the water. Computer programs are used to precisely infer water velocity patterns by analyzing consecutive video images of particle motion. The effect of forward swimming behavior during suction feeding (termed 'ram feeding') on the water flow pattern created by suction will be measured. In addition, the forces exerted on prey by suction flows will be measured both by inferences from the water flow patterns and directly through the use of force transducers to test the hypothesis that the acceleration reaction, a previously ignored force that is generated by flows of changing velocity, outpaces the more familiar drag forces that are experienced by prey caught in a flow. An important role for accelerationreaction may greatly alter the picture of forces that are experienced by prey, and may help to explain the explosive nature of suction feeding, which can occur in less than 10 msec, one of the fastest feeding behaviors seen in vertebrates. A second part of the project will be directed at understanding the variation among fish species in suction feeding performance. Four species in the freshwater fish family Centrarchidae will be studied representing the range of suction feeding abilities known in this family. A parallel series of four species of the Cichlidae representing a similar range of ecomorphological diversity will also be studied. Peak suction flow capacity will be measured for each species using DPIV while mouth and oral expansion will be measured using an ultrasound method, sonomicrometry, that permits precise quantification of changes in the internal dimensions of the oral cavity during feeding. Broader impacts of this project may involve application of information on unsteady flows to enhance forces exerted on target bodies in the development of surgical suction devices. This research will provide training for a postdoctoral researcher, a female graduate student, and an undergraduate from an underrepresented group. The postdoc will gain teaching experience and the graduate student will design a laboratory exercise on aquatic feeding for use in a course on vertebrate evolution. A website will be developed that provides information about suction feeding and movie clips of feeding fish for use by university instructors in organismal biology courses.