Seasonality and brain size are negatively associated in frogs: evidence for the expensive brain framework
Seasonality and brain size are negatively associated in frogs: evidence for the expensive brain framework
复制标题
青蛙的季节性和大脑大小呈负相关：昂贵的大脑框架的证据
DOI：
10.1038/s41598-017-16921-1
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发表时间：
2017-11-30
影响因子：
4.6
通讯作者：
Kotrschal, Alexander
中科院分区：
文献类型：
--
作者：
Luo, Yi;Zhong, Mao Jun;Kotrschal, Alexander
季节性环境的挑战被认为有助于大脑的进化，但以何种方式存在争议。根据认知缓冲假设（CBH），大脑的大小应该随着季节的变化而增加，因为更大的大脑的认知益处应该有助于克服食物短缺的时期，例如，增加行为灵活性。然而，根据昂贵的大脑框架（EBF），大脑大小应该随着季节性而减小，因为较小的大脑在食物短缺时期可以带来精力充沛的好处。经验证据是不确定的，主要限于恒温动物。在这里，我们使用系统发育比较分析来测试30种无尾两栖类（青蛙）经历了广泛的温度和降水的季节性对大脑进化的影响。我们的研究结果支持EBF，因为相对大脑的大小和视顶盖的大小与温度的变化呈负相关。相比之下，我们发现降水量的变化和旱季的长度与大脑大小或其他主要大脑区域的大小之间没有联系。我们认为，季节性引起的食物短缺导致更高的温度变化限制了无尾类动物大脑大小的演变。因此，季节性较弱的环境可能有助于变温动物进化出更大的大脑。
The challenges of seasonal environments are thought to contribute to brain evolution, but in which way is debated. According to the Cognitive Buffer Hypothesis (CBH) brain size should increase with seasonality, as the cognitive benefits of a larger brain should help overcoming periods of food scarcity via, for instance, increased behavioral flexibility. However, in line with the Expensive Brain Framework (EBF) brain size should decrease with seasonality because a smaller brain confers energetic benefits in periods of food scarcity. Empirical evidence is inconclusive and mostly limited to homoeothermic animals. Here we used phylogenetic comparative analyses to test the impact of seasonality on brain evolution across 30 species of anurans (frogs) experiencing a wide range of temperature and precipitation. Our results support the EBF because relative brain size and the size of the optic tectum were negatively correlated with variability in temperature. In contrast, we found no association between the variability in precipitation and the length of the dry season with either brain size or the sizes of other major brain regions. We suggest that seasonality-induced food scarcity resulting from higher variability in temperature constrains brain size evolution in anurans. Less seasonal environments may therefore facilitate the evolution of larger brains in poikilothermic animals.