Fox Stephanie, Muller Martin N, Peña Natalia Camargo, González Nicole Thompson, Machanda Zarin, Otali Emily, Wrangham Richard, Thompson Melissa Emery
University of California Santa Barbara, Goleta, USA.
University of New Mexico, Albuquerque, USA.
Anim Behav. 2024 Nov;217:21-38. doi: 10.1016/j.anbehav.2024.08.008. Epub 2024 Sep 16.
Strong, affiliative bonds often function to facilitate social competition through cooperative defence of resources, but the benefits of social bonds may be low when direct competition is less intense or less beneficial. In such cases, one possible outcome is that relationships are weak and undifferentiated. Alternatively, negotiating stable, selectively tolerant relationships may be a strategy to mitigate the costs and risks of sharing space when direct competition is undesirable. We investigated dyadic social tolerance among wild adult female chimpanzees, who engage in low rates of affiliation and aggression amongst one another. While females associate with one another at different rates, these patterns could reflect shared patterns of behaviour (e.g., ranging) rather than social preference or variation in relationship quality. We first determined whether patterns of dyadic spatial association (five-meter proximity) were differentiated and stable over time. To assess whether dyadic spatial association reflected preference and variation in social tolerance, we tested whether spatial association was actively maintained by waiting and following behaviour, and associated with decreased aggression and increased cofeeding. Spatial associations were differentiated, and stronger associations were more stable. Frequent associates used following and waiting behaviour to actively maintain associations. Association positively predicted time cofeeding and negatively predicted aggression. These patterns were true among related and unrelated dyads. Among unrelated females, dyads with stronger associations maintained proximity more mutually. This study highlights social tolerance as a stable relationship attribute that can predict and explain patterns of behaviour and social network structure, distinct from, or in the absence of, affiliation.
强大的亲和纽带通常通过对资源的合作性防御来促进社会竞争，但当直接竞争不那么激烈或益处较小时，社会纽带的益处可能就会降低。在这种情况下，一种可能的结果是关系薄弱且无差异。或者，当直接竞争不可取时，协商稳定、有选择性容忍的关系可能是一种减轻共享空间成本和风险的策略。我们研究了野生成年雌性黑猩猩之间的二元社会容忍度，它们之间的亲和与攻击发生率较低。虽然雌性之间以不同频率相互交往，但这些模式可能反映的是共同的行为模式（例如活动范围），而非社会偏好或关系质量的差异。我们首先确定二元空间关联模式（五米近距离）是否随时间而有差异且稳定。为评估二元空间关联是否反映了社会容忍度的偏好和差异，我们测试了空间关联是否通过等待和跟随行为而积极维持，以及是否与攻击减少和共同进食增加相关。空间关联是有差异的，且更强的关联更稳定。频繁交往的个体通过跟随和等待行为积极维持关联。关联正向预测共同进食时间，负向预测攻击行为。这些模式在有亲缘关系和无亲缘关系的二元组中都成立。在无亲缘关系的雌性中，关联更强的二元组相互间保持更近的距离。这项研究强调社会容忍度是一种稳定的关系属性，它可以预测和解释行为模式及社会网络结构，与亲和关系不同，或者在没有亲和关系的情况下也是如此。
