Glazier Douglas S, Borrelli Jonathan J, Hoffman Casandra L
Department of Biology, Juniata College, Huntingdon, PA 16652, USA.
Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Biology (Basel). 2020 Feb 25;9(3):40. doi: 10.3390/biology9030040.
Little is known about how predators or their cues affect the acquisition and allocation of energy throughout the ontogeny of prey organisms. To address this question, we have been comparing the ontogenetic body-mass scaling of various traits related to energy intake and use between populations of a keystone amphipod crustacean inhabiting freshwater springs, with versus without fish predators. In this progress report, we analyze new and previously reported data to develop a synthetic picture of how the presence/absence of fish predators affects the scaling of food assimilation, fat content, metabolism, growth and reproduction in populations of located in central Pennsylvania (USA). Our analysis reveals two major clusters of 'symmorphic allometry' (parallel scaling relationships) for traits related to somatic versus reproductive investment. In the presence of fish predators, the scaling exponents for somatic traits tend to decrease, whereas those for reproductive traits tend to increase. This divergence of scaling exponents reflects an intensified trade-off between somatic and reproductive investments resulting from low adult survival in the face of size-selective predation. Our results indicate the value of an integrated view of the ontogenetic size-specific energetics of organisms and its response to both top-down (predation) and bottom-up (resource supply) effects.
关于捕食者或其线索如何影响猎物生物个体发育过程中能量的获取和分配，我们知之甚少。为了解决这个问题，我们一直在比较栖息于淡水泉中的一种关键双足甲壳动物种群在有和没有鱼类捕食者的情况下，与能量摄入和利用相关的各种性状的个体发育体重缩放情况。在这份进展报告中，我们分析了新的和先前报告的数据，以形成一幅关于鱼类捕食者的有无如何影响位于美国宾夕法尼亚州中部的种群中食物同化、脂肪含量、新陈代谢、生长和繁殖缩放的综合图景。我们的分析揭示了与体细胞投资和生殖投资相关的性状的两个主要“对称异速生长”（平行缩放关系）集群。在有鱼类捕食者的情况下，体细胞性状的缩放指数往往会降低，而生殖性状的缩放指数往往会增加。缩放指数的这种差异反映了在面对大小选择性捕食时成年个体存活率较低导致的体细胞投资和生殖投资之间权衡的加剧。我们的结果表明了对生物体个体发育大小特异性能量学及其对自上而下（捕食）和自下而上（资源供应）效应的响应进行综合研究的价值。
