Data from: Ambient temperature influences tolerance to plant secondary compounds in a mammalian herbivore

Growing evidence suggests that plant secondary compounds (PSCs) ingested by mammals become more toxic at elevated ambient temperatures, a phenomenon known as temperature-dependent toxicity. We investigated temperature-dependent toxicity in the desert woodrat (Neotoma lepida), a herbivorous rodent that naturally encounters PSCs in creosote bush (Larrea tridentata), which is a major component of its diet. First, we determined the maximum dose of creosote resin ingested by woodrats at warm (28–29°C) or cool (21–22°C) temperatures. Second, we controlled the daily dose of creosote resin ingested at warm, cool and room (25°C) temperatures, and measured persistence in feeding trials. At the warm temperature, woodrats ingested significantly less creosote resin; their maximum dose was two-thirds that of animals at the cool temperature. Moreover, woodrats at warm and room temperatures could not persist on the same dose of creosote resin as woodrats at the cool temperature. Our findings demonstrate that warmer temperatures reduce PSC intake and tolerance in herbivorous rodents, highlighting the potentially adverse consequences of temperature-dependent toxicity. These results will advance the field of herbivore ecology and may hone predictions of mammalian responses to climate change.

越来越多的证据表明，哺乳动物摄入的植物次生代谢物（plant secondary compounds, PSCs）在环境温度升高时毒性会增强，这一现象被称为温度依赖性毒性（temperature-dependent toxicity）。我们以植食性啮齿动物沙漠林鼠（Neotoma lepida）为研究对象开展相关实验，该物种的自然饮食以三齿拉瑞阿（Larrea tridentata，俗称creosote bush）为主要组成部分，天然会接触该植物产生的PSCs。首先，我们测定了沙漠林鼠在温暖（28–29℃）与凉爽（21–22℃）环境下的最大可摄入三齿拉瑞阿树脂剂量；其次，我们在温暖、凉爽与室温（25℃）三种温度条件下控制沙漠林鼠每日摄入的三齿拉瑞阿树脂剂量，并通过摄食试验测定其对该树脂的耐受持久性。实验结果显示，温暖环境下的沙漠林鼠摄入的三齿拉瑞阿树脂剂量显著更低，其最大可摄入剂量仅为凉爽环境下个体的三分之二；此外，温暖与室温环境下的沙漠林鼠无法像凉爽环境下的个体那样耐受相同剂量的三齿拉瑞阿树脂。本研究结果证实，更高的环境温度会降低植食性啮齿动物对PSCs的摄入能力与耐受水平，凸显了温度依赖性毒性可能带来的潜在负面影响。上述研究成果将推动植食动物生态学领域的发展，并可为哺乳动物应对气候变化的响应预测提供更精准的优化依据。