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

生物体的大小影响着生物体的生理、行为和群落水平的相互作用，但人们对实际控制它的因素知之甚少。小型哺乳动物食草动物被隔离在岛屿上，减轻了捕食和竞争压力，为研究体型选择提供了理想的环境。与大陆栖息地相比，海岛食草动物的食物供应不仅不那么多样化，而且也不那么丰富。理论预测，体型较大的动物会有较低的特定代谢率，但它们的肠道大小却大致等长。因此，对体型的选择可能是因为大型动物从低质量食物中提取能量的效率更高。我们将采用比较的方法来检验这一假设。对大小的选择将在两个岛屿上进行衡量--一个岛屿展示巨人，另一个岛屿没有巨人。将测量和分析饲料组成和质量，然后与与体型相关的生物学特性相关。

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.