Nutritional constraints on brain evolution: sodium and nitrogen limit brain size

Nutrition has been hypothesized as an important constraint on brain evolution. However, it is unclear whether the availability of specific nutrients or the difficulty of locating high quality diets limits brain evolution, especially over long periods of time. We show that dietary nutrient content predicted brain size across 42 species of butterflies. Brain size, relative to body size, was associated with the sodium and nitrogen content of a species’ diet. There was no evidence that host plant apparency (measured by plant height) was related to brain evolution. The timing of diet shifts varied from 3.5 to 90 million years ago, but nutritional constraints did not lessen over time as species adapted to a diet. While nutrition was linked to overall brain volume, there was no evidence that nutrition was related to the relative size of individual brain regions. Lab rearing experiments confirmed the underlying assumption of most comparative studies that the majority of interspecific trait vari...营养已被假设为大脑演化的重要限制因素。然而目前尚不清楚，究竟是特定营养素的可获得性，还是获取优质食源的难度限制了大脑演化，尤其是在长期演化尺度下。本研究显示，在42个蝴蝶物种中，膳食营养素含量可预测其大脑尺寸。相较于体型的脑容量（即脑体比）与该物种膳食中的钠和氮含量显著相关。未发现寄主植物可见度（以株高作为衡量指标）与大脑演化存在关联的证据。食性转变的时间跨度介于350万至9000万年前，但随着物种适应其食性，营养限制并未随时间推移而减轻。尽管营养与整体脑容量存在关联，但未发现营养与单个脑区的相对大小存在关联的证据。室内饲养实验验证了大多数比较研究的核心假设：即多数物种间的性状变异……