Dissertation Research: Diet Selection of the North American Pika: The Effects of Plant Morphology, Nutrients, and Plant Secondary Compounds

食草动物面临着一种复杂的营养和毒素的食物资源基础。由于这种复杂性，人们对食草动物的饮食选择知之甚少。鼠兔是生活在山区的哺乳动物(与兔子有亲缘关系)，与许多其他小型哺乳动物不同，它们整个冬天都很活跃。在冬季，鼠兔依靠前一年夏天收集的储存的植被(“海绵”)生存。储存在海鞘中的冬季食物与鼠兔在夏天吃的植物有很大的不同，尽管两者都是同时采集的。这个项目的重点是确定导致这些不同饮食选择的因素。假设1)鼠兔选择营养丰富而毒素不足的夏季饮食，但它们冬季饮食的选择比简单地避免植物毒素更复杂；2)鼠兔在冬季饮食中操纵植物毒素，这些假设将得到测试。关于营养素、毒素和可用食用植物形态的数据将被收集并用于检验这些假说。这项研究的意义不仅仅是理解鼠兔的饮食选择问题。确定控制饮食选择的因素，可能会为动物园的食草动物带来更好的饮食。此外，这些信息可以用来利用植物毒素来自然调节食草性害虫的数量，特别是啮齿动物。

Herbivores confront a food resource base with a complex assortment of nutrients and toxins. Because of this complexity, diet selection in herbivores is poorly understood. Pikas (Ochotona princeps) are mammals (related to rabbits) that inhabit mountainous regions and unlike many other small mammals, remain active all winter. During the winter, pikas survive on stored vegetation ("haypiles"), collected during the previous summer. The winter diet stored in the haypile differs considerably from the plants that pikas consume in the summer, although both are collected simultaneously. This project focuses on identifying the factors responsible for these different diet choices. Hypotheses that 1) pikas select their summer diet to be nutrient-rich and toxin-poor, but that their winter diet choice is more intricate than simple avoidance of plant toxins; and that 2) pikas manipulate plant toxins in their winter diet, will be tested. Data on nutrients, toxins, and morphologies of available food plants will be collected and used to test these hypotheses. The significance of the research extends beyond understanding the question of diet selection in pikas. Identifying the factors governing diet selection, may lead to better diets for herbivorous animals in zoos. Moreover, this information could be used to exploit plant toxins to naturally regulate herbivorous pest populations, especially rodents.