McClintock James B, Lawrence John M
Department of Biology, University of South Florida, 33620, Tampa, FL, USA.
Oecologia. 1985 May;66(2):291-298. doi: 10.1007/BF00379867.
Luidia clathrata show a strong preference for the infaunal bivalve Mulinia lateralis in Tampa Bay, Florida. Quantitative and qualitative changes in diet occurred over a 7-month period. Individuals may shift from intraoral macrofaunal feeding to intra- and extraoral detrital feeding during periods of low macrofaunal availability. In the laboratory L. clathrata showed switching behavior, feeding disproportionately on the most abundant of two simulataneously presented food models. This switching mechanism may be related to either contact-chemoreceptive rejection of lowdensity food or enhanced distance-chemoreception of high density food. The use of standardized food models eliminated the possibility that handling time was important in switching behavior. Both fed and starved individuals showed functional responses to changes in prey density. However starved individuals ingested greater numbers of prey and spent more time foraging than did fed individuals. Switching and functional response behaviors may be important in promoting nutritional uptake and in causing density-dependent mortality of prey populations. Movement patterns of L. clathrata are directional in the absence of bivalve prey, but become non-directional once patches of prey are encountered. This allows individuals to remain in areas of high prey density. Luidia clathrata has characteristics of an optimal forager, where energy is maximized per unit feeding time.
在佛罗里达州坦帕湾，网瘤海星对底内双壳贝类侧偏穆氏蛤表现出强烈的偏好。在7个月的时间里，其饮食发生了定量和定性的变化。在大型底栖动物数量较少的时期，个体可能会从口内大型底栖动物摄食转变为口内和口外碎屑摄食。在实验室中，网瘤海星表现出转换行为，对同时呈现的两种食物模型中数量最多的那种食物过度摄食。这种转换机制可能与对低密度食物的接触化学感受性排斥或对高密度食物的增强的距离化学感受有关。使用标准化食物模型排除了处理时间在转换行为中起重要作用的可能性。喂食和饥饿的个体都对猎物密度的变化表现出功能反应。然而，饥饿的个体比喂食的个体摄取更多的猎物，并且花费更多时间觅食。转换和功能反应行为可能在促进营养摄取和导致猎物种群的密度依赖性死亡方面很重要。在没有双壳贝类猎物的情况下，网瘤海星的移动模式是有方向的，但一旦遇到猎物斑块，就会变得无方向。这使个体能够留在猎物密度高的区域。网瘤海星具有最佳觅食者的特征，即在单位摄食时间内能量最大化。
