Dissertation Research: A Nutritional Basis for Insular Gigantism in Small Mammalian Herbivores

体型大小影响着生物体的生理、行为和群落水平的相互作用，但实际上对控制它的因素知之甚少。小型食草哺乳动物，孤立在岛屿上，减轻了捕食和竞争压力，为研究体型选择提供了理想的条件。与大陆栖息地相比，岛上食草动物的食物供应不仅缺乏多样性，而且也不够丰富。理论预测，较大的动物将有较低的特定代谢率，但他们的肠道大小增加大约等量。因此，体型选择可能是由于大型动物从低质量食物中提取能量的效率更高。将采用比较方法来检验这一假设。大小选择将在两个岛上进行测量——一个岛上有巨人症，另一个岛上没有。将测量和分析饲粮组成和品质，然后将其与体型相关的生物学性状相关联。

Body size influences the physiology, behavior and community level interactions of organisms, but little is actually known about the factors controlling it. Small mammalian herbivores, isolated on islands and relieved of predation and competition pressures, offer an ideal situation for the study of selection on size. Island herbivores subsist on a food supply which is not only less diverse, but less abundant than in mainland habitats. Theory predicts that larger animals will have lower specific metabolic rates, yet their gut size increases approximately isometrically. Thus, selection on body size may result from the greater efficiency of larger animals in extracting energy from low-quality foods. A comparative approach will be used to test this hypothesis. Selection on size will be measured on two islands--one where gigantism is exhibited, one where it is not. Dietary composition and quality will be measured and analyzed, then related to biological traits associated with size.