Warm vegetarians? Heat waves and diet shifts in tadpoles
Warm vegetarians? Heat waves and diet shifts in tadpoles
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DOI：
10.1002/ecy.1541
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发表时间：
2016-11-01
期刊：
影响因子：
4.8
通讯作者：
Rebelo, R.
中科院分区：
文献类型：
--
作者：
Carreira, B. M.;Segurado, P.;Rebelo, R.
温度在决定变温动物的摄食偏好方面起着重要作用。鉴于当前气候变化引起的温度升高，杂食性变温动物可能会向更高的食草性饮食转变，以优化能量摄入。这种饮食变化也可能发生在热浪期间，预计未来热浪将变得更加频繁、强烈、持续时间更长。本文研究了不同持续时间的热浪对杂食性无尾蝌蚪摄食偏好的影响，以及这些选择对其幼虫生活史的影响。在实验室实验中，我们给三种蝌蚪喂食动物、植物或混合食物，并将它们暴露在短热浪（类似于这些物种目前所经历的热浪）或长热浪（预计在气候变化下会增加）中。我们使用稳定同位素估计了饲喂混合饮食的蝌蚪的饮食选择，并记录了蝌蚪的存活和生长、幼虫期和变态质量。蝌蚪的摄食偏好与它们的热背景有关，在自然界中，草食性随着繁殖温度的升高而增加。在较高温度下，生存、生长和发育的模式通常支持肉食性饮食效率的降低和草食性饮食效率的提高或相对质量的提高。这三个物种在至少一种热浪处理中都增加了食草性，但不同物种的反应不同。在一个物种中，饮食转向更高的食草性是不适应的，但在另外两个物种中是有益的。变暖环境下杂食性变温动物的高食草性可能对物种产生不同的影响，并进一步促进淡水环境结构和功能的变化。
Temperature can play an important role in determining the feeding preferences of ectotherms. In light of the warmer temperatures arising with the current climatic changes, omnivorous ectotherms may perform diet shifts toward higher herbivory to optimize energetic intake. Such diet shifts may also occur during heat waves, which are projected to become more frequent, intense, and longer lasting in the future. Here, we investigated how heat waves of different duration affect feeding preferences in omnivorous anuran tadpoles and how these choices affect larval life history. In laboratory experiments, we fed tadpoles of three species on animal, plant, or mixed diet and exposed them to short heat waves (similar to the heat waves these species experience currently) or long heat waves (predicted to increase under climate change). We estimated the dietary choices of tadpoles fed on the mixed diet using stable isotopes and recorded tadpole survival and growth, larval period, and mass at metamorphosis. Tadpole feeding preferences were associated with their thermal background, with herbivory increasing with breeding temperature in nature. Patterns in survival, growth, and development generally support decreased efficiency of carnivorous diets and increased efficiency or higher relative quality of herbivorous diets at higher temperatures. All three species increased herbivory in at least one of the heat wave treatments, but the responses varied among species. Diet shifts toward higher herbivory were maladaptive in one species, but beneficial in the other two. Higher herbivory in omnivorous ectotherms under warmer temperatures may impact species differently and further contribute to changes in the structure and function of freshwater environments.