Skopec Michele M, Haley Shannon, Torregrossa Ann-Marie, Dearing M Denise
Department of Zoology, Weber State University, Ogden, Utah 84408, USA.
Physiol Biochem Zool. 2008 Jul-Aug;81(4):426-33. doi: 10.1086/589106.
Dietary specialization is thought to be rare in mammalian herbivores as a result of either a limitation in their detoxification system to metabolize higher doses of plant secondary compounds or deficiencies in nutrients present in a diet composed of a single species of plant. Neotoma macrotis is an oak specialist, whereas Neotoma lepida is a dietary generalist when sympatric with N. macrotis. We hypothesized that N. macrotis would have a higher tolerance for and digestibility of oak. We determined the two species' tolerances for oak by feeding them increasing concentrations of ground oak leaves until they could no longer maintain body mass. The highest concentration on which both species maintained body mass was 75% oak. There were no differences between the species in their abilities to digest dry matter, nitrogen, or fiber in the oak diets. The species' similar tolerances for oak were probably due to their similar abilities to digest and potentially assimilate the ground oak leaves.
由于哺乳动物食草动物的解毒系统在代谢高剂量植物次生化合物方面存在局限性，或者由单一植物物种组成的饮食中存在营养缺乏，饮食特化在哺乳动物食草动物中被认为是罕见的。大耳林鼠是橡树专家，而与大耳林鼠同域分布时，白足林鼠是饮食通才。我们假设大耳林鼠对橡树具有更高的耐受性和消化率。我们通过给它们喂食浓度不断增加的磨碎橡树叶来确定这两个物种对橡树的耐受性，直到它们无法再维持体重。两个物种都能维持体重的最高浓度是75%的橡树叶。在橡树饮食中，两个物种在消化干物质、氮或纤维的能力上没有差异。这两个物种对橡树的相似耐受性可能是由于它们消化并潜在同化磨碎橡树叶的能力相似。
