Rebout Nancy, Desportes Christine, Thierry Bernard
Centre National de la Recherche Scientifique, Université de Strasbourg, Institut Pluridisciplinaire Hubert Curien, Strasbourg, France.
Aggress Behav. 2017 Sep;43(5):513-520. doi: 10.1002/ab.21709. Epub 2017 Apr 27.
The clumped distribution of food resources promotes food defensibility and can lead to the monopolizing of resources by high-ranking individuals. However, the balance of power is set at different levels according to societies, meaning that resource partitioning should vary between them. This study investigates whether dominance asymmetry and resource partitioning are related in non-human primates by comparing two species with contrasting social styles, namely rhesus macaques (Macaca mulatta) which display strong social intolerance and a steep gradient of dominance, and Tonkean macaques (Macaca tonkeana), which exhibit higher levels of tolerance and more balanced dominance relationships. Study groups were kept in semi-free ranging conditions. Animals were provided with fruit in three different clumped conditions during 30-min trials. We found that higher-ranking rhesus macaques had priority for the access to fruit: these individuals spent longer in the feeding area in the first 10-min period of trials, while lower-ranking individuals had diminished access to fruit under the most clumped condition; this was associated with sustained agonistic interactions. Dominance effects were weaker in Tonkean macaques. They exhibited co-feeding between high- and low-ranking individuals in the first period; there was no significant effect of dominance even in the most clumped condition; and frequencies of agonistic interactions remained moderate relative to the number of individuals present in the feeding area. These results show that food resources were more equitably distributed among group members in tolerant macaques than in their intolerant counterparts. Dominance gradient and social tolerance may be considered as two aspects of the same phenomenon.
食物资源的聚集分布促进了食物防御能力，可能导致高等级个体对资源的垄断。然而，根据不同社会群体，权力平衡处于不同水平，这意味着资源分配在不同群体间存在差异。本研究通过比较两种具有不同社会风格的非人灵长类动物，即表现出强烈社会不容忍和陡峭等级梯度的恒河猴（Macaca mulatta），以及表现出更高容忍度和更平衡等级关系的托氏猕猴（Macaca tonkeana），来探究等级不对称与资源分配在非人灵长类动物中是否相关。研究群体被置于半自由放养条件下。在30分钟的试验期间，为动物提供三种不同聚集程度的水果。我们发现，高等级恒河猴在获取水果方面具有优先权：这些个体在试验的前10分钟内在进食区域停留的时间更长，而低等级个体在最聚集的条件下获取水果的机会减少；这与持续的争斗互动有关。托氏猕猴的等级效应较弱。它们在第一阶段表现出高等级和低等级个体共同进食；即使在最聚集的条件下，等级也没有显著影响；相对于进食区域中的个体数量，争斗互动的频率保持适中。这些结果表明，与不容忍的猕猴相比，宽容的猕猴群体成员之间的食物资源分配更为公平。等级梯度和社会容忍度可被视为同一现象的两个方面。
