调节多种营养素摄入量时的最佳觅食

越来越多的证据表明，许多动物试图独立调节多种营养素的摄入量，而不是在受到限制的情况下最大限度地增加能量摄入量。在食草动物等动物的复杂饮食中，有时食用营养不平衡的食物是不可避免的，这迫使这些动物在摄入太多食物中相对过量的营养素与摄入太少的食物中本身就匮乏的营养素之间进行权衡。这种情况在现有的觅食理论公式中没有得到充分的体现。在这里，我们使用一种将营养的状态空间模型与Tilman的资源剥削模型(Tilman 1982，资源竞争和社区结构，普林斯顿：普林斯顿大学出版社)相结合的方法，提供了适合这种情况的必要理论。我们的方法是在营养空间上构建一个平滑的适合度景观，以一个不产生适合度成本的“目标”摄入量为中心，这导致了基于景观形状的泰勒级数近似的简单可能的适合度景观的自然分类。接下来，我们研究了如何使用动物性能的直接测量作为通用货币，在实验中评估对多种营养素的需求，以便动物的营养策略可以映射到性能表面，包括当饲喂不理想的食物时，调节摄取点和营养平衡点的位置。我们调查了已发表的数据，并进行了一项实验，以绘制出一种很常见的（generalist字面意思，多面手，通才，此处我认为是说这个虫子很常见，适合研究）的叶毛虫--海灰翅夜蛾(Spotortera Littoralis)的性能图景。

原文: 

There is growing evidence that, rather than maximizing energy intake subject to constraints, many animals attempt to regulate intake of multiple nutrients independently. In the complex diets of animals such as herbivores, the consumption of nutritionally imbalanced foods is sometimes inevitable, forcing trade-offs between eating too much of nutrients present in the foods in relative excess against too little of those in deficit. Such situations are not adequately represented in existing formulations of foraging theory. Here we provide the necessary theory to fit this case, using an approach that combines state-space models of nutrition with Tilman’s models of resource exploitation (Tilman 1982, Resource Competition and Community Structure, Princeton: Princeton University Press). Our approach was to construct a smooth fitness landscape over nutrient space, centred on a ‘target’ intake at which no fitness cost is incurred, and this leads to a natural classification of the simple possible fitness landscapes based on Taylor series approximations of landscape shape. We next examined how needs for multiple nutrients can be assessed experimentally using direct measures of animal performance as the common currency, so that the nutritional strategies of animals can be mapped on to the performance surface, including the position of regulated points of intake and points of nutrient balance when fed suboptimal foods. We surveyed published data and conducted an experiment to map out the performance landscape of a generalist leaffeeding caterpillar, Spodoptera littoralis.

参考文献

Simpson, S.J., Sibly, R.M., Lee, K.P., Behmer, S.T., Raubenheimer, D., 2004. Optimal foraging when regulating intake of multiple nutrients. Animal Behaviour 68, 1299-1311.