Department of Anthropology, Northern Illinois University, DeKalb, IL, 60115.
Am J Phys Anthropol. 2014 Jan;153(1):78-91. doi: 10.1002/ajpa.22412. Epub 2013 Nov 7.
Primate field studies often identify "lean seasons," when preferred foods are scarce, and lower-quality, abundant foods (fallback foods) are consumed. Here, we quantify the nutritional implications of these terms for two diademed sifaka groups (Propithecus diadema) in Madagascar, using detailed feeding observations and chemical analyses of foods. In particular, we sought to understand 1) how macronutrient and energy intakes vary seasonally, including whether these intakes respond in similar or divergent ways; 2) how the amount of food ingested varies seasonally (including whether changes in amount eaten may compensate for altered food quality); and 3) correlations between these variables and the degree of frugivory. In the lean season, sifakas shifted to non-fruit foods (leaves and flowers), which tended to be high in protein while low in other macronutrients and energy, but the average composition of the most used foods in each season was similar. They also showed dramatic decreases in feeding time, food ingested, and consequently, daily intake of macronutrients and energy. The degree of frugivory in the daily diet was a strong positive predictor of feeding time, amount ingested and all macronutrient and energy intakes, though season had an independent effect. These results suggest that factors restricting how much food can be eaten (e.g., handling time, availability, or intrinsic characteristics like fiber and plant secondary metabolites) can be more important than the nutritional composition of foods themselves in determining nutritional outcomes-a finding with relevance for understanding seasonal changes in behavior, life history strategies, competitive regimes, and conservation planning.
灵长类动物的野外研究经常会发现“瘦季”，此时，首选食物变得稀缺，而低质量、丰富的食物（替代食物）则被消耗。在这里，我们使用详细的喂养观察和食物的化学分析，为马达加斯加的两个冕狐猴群体（Propithecus diadema）量化了这些术语的营养含义。特别是，我们试图了解 1）宏量营养素和能量的摄入量如何随季节变化，包括这些摄入量是否以相似或不同的方式做出反应；2）季节性食物摄入量如何变化（包括进食量的变化是否可以弥补食物质量的变化）；3）这些变量与果实摄入量之间的相关性。在瘦季，冕狐猴转向非果实食物（叶子和花朵），这些食物往往蛋白质含量高，而其他宏量营养素和能量含量低，但每个季节最常食用的食物的平均成分相似。它们还表现出喂食时间、摄入食物量以及由此导致的宏量营养素和能量日摄入量的急剧减少。每日饮食中的果实摄入量是喂食时间、摄入食物量以及所有宏量营养素和能量摄入量的强烈正预测因子，尽管季节有独立的影响。这些结果表明，限制可以进食的食物量的因素（例如处理时间、可用性或内在特征，如纤维和植物次生代谢物）可能比食物本身的营养成分更重要，从而决定营养结果——这一发现对于理解行为、生活史策略、竞争格局和保护规划中的季节性变化具有重要意义。
