Sharp ecological boundaries often present animals with abrupt transitions in various resources, including the availability of food, potentially creating strong selective gradients. Yet little is known concerning how animals respond to abrupt shifts in resources, especially when gene flow may limit local adaptation. Here, we used DNA metabarcoding and untargeted metabolomics of fecal samples to begin characterizing the foraging ecology of two closely related rodents (Neotoma bryanti and N. lepida) across a sharp ecological boundary. We find abrupt transitions in diet and metabolomic signatures that coincide with the rapid habitat transition. Further, we show that individuals have habitat-specific diets that are dominated by distinctly toxic plants that likely require different metabolic processing. Our approach allows detailed characterization of diet and metabolic processing of food plants, which can provide evolutionary ecologists and wildlife biologists much needed insight into the nutritional and physiological ecology of the systems they study and manage.

中文翻译：

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跨越急剧生态转变的小型哺乳动物饮食和代谢组学的精细分化

尖锐的生态边界常常使动物在各种资源（包括食物的可用性）中突然转变，可能会产生强烈的选择性梯度。然而，人们对动物如何应对资源的突然变化知之甚少，尤其是当基因流动可能会限制局部适应时。在这里，我们使用粪便样本的 DNA 元条形码和非靶向代谢组学开始表征两种密切相关的啮齿动物（Neotoma bryanti 和 N. lepida）跨越尖锐生态边界的觅食生态。我们发现饮食和代谢组学特征的突然转变与栖息地的快速转变相吻合。此外，我们表明个体具有特定于栖息地的饮食，这些饮食以明显有毒的植物为主，这些植物可能需要不同的代谢处理。