Kurihara Yosuke, Hanya Goro
Primate Research Institute, Kyoto University, Kanrin 41-2, Inuyama, Aichi, 484-8506, Japan.
Primates. 2017 Jul;58(3):413-422. doi: 10.1007/s10329-017-0607-x. Epub 2017 Apr 20.
Quantifying the energy balance is essential for testing socio-ecological models. To reveal costs and benefits of group living in Japanese macaques from the perspective of feeding competition, Kurihara and Hanya (Am J Primatol 77:986-1000, 2015) previously compared feeding behavior between two different-sized groups of macaques (larger group 30-35 individuals; smaller group 13-15 individuals) in the coastal forest of Yakushima, Japan. The results suggested that the larger group exhibited greater feeding effort because of intragroup scramble competition and that the smaller group suffered from higher travel costs, possibly owing to intergroup contest competition. However, it remained unclear whether the behavioral differences affected their energy budgets. The present study examined energetic consequences of the different feeding behaviors in the two groups. Using behavioral data from 10 to 13 adult females and nutritional composition of food items, we compared ingestion rates, energetic/nutritional content of diet, and energy budgets between the two groups. Ingestion rates and energetic/nutritional content of diet did not differ between the two groups. Despite the higher feeding effort of the larger group, energy intake did not differ between the two groups. Energy expenditure did not differ between the two groups because higher travel costs were negated by lower feeding effort in the smaller group. Consequently, the energy balance did not differ between the two groups. We demonstrated that the behavioral measures of feeding competition were not translated into their energetic condition; moreover, our findings re-emphasize the importance of quantifying behavioral and fitness measures for interpreting variation in feeding behavior properly.
量化能量平衡对于检验社会生态模型至关重要。为了从觅食竞争的角度揭示日本猕猴群体生活的成本和收益，栗原和羽谷（《美国灵长类学杂志》77:986 - 1000，2015年）此前比较了日本屋久岛沿海森林中两组不同规模猕猴（较大群体30 - 35只个体；较小群体13 - 15只个体）的觅食行为。结果表明，较大群体由于组内争夺竞争而表现出更大的觅食努力，而较小群体可能由于组间竞争而承受更高的移动成本。然而，尚不清楚这些行为差异是否影响了它们的能量预算。本研究考察了两组不同觅食行为的能量后果。利用10至13只成年雌性的行为数据和食物的营养成分，我们比较了两组之间的摄入率、饮食的能量/营养含量以及能量预算。两组之间的摄入率和饮食的能量/营养含量没有差异。尽管较大群体的觅食努力更大，但两组之间的能量摄入没有差异。两组之间的能量消耗没有差异，因为较小群体较低的觅食努力抵消了较高的移动成本。因此，两组之间的能量平衡没有差异。我们证明了觅食竞争的行为指标并没有转化为它们的能量状况；此外，我们的研究结果再次强调了量化行为和适应性指标对于正确解释觅食行为变化的重要性。
