Environmental variations can influence the extent to which individuals interact with other individuals by changing the value of grouping. It is well known that many species can form and disband groups, often in response to the distribution and abundance of resources. While previous studies showed that resources influence the broad-scale structure of animal groups, knowledge gaps remain on whether they affect fine-scale patterns of association among individuals within groups. We quantify association patterns in African lions while simultaneously monitoring the abundance and distribution of prey. We test how social and ecological factors, including individual trait (age, sex, reproductive state) similarity and prey availability (prey abundance, dispersion, herd size and body size) affect within-pride social structure in African lions. We found that individual decisions about associates depended on resource availability with individuals associating equally across all members of the pride when prey herds were scarce, aggregated or large bodied, and associating more exclusively (in subgroups of preferred associates) when prey herds were abundant, dispersed or small bodied. Individuals within lion prides seemed to be buffering against changes in prey availability by modulating their strength and density of connections with conspecifics when prides split into subgroups. The strength and density of connections among individuals within subgroups was greater when prey herds were large and lower when prey herds were dispersed or large bodied. Our findings suggest that individual lions are making social decisions at both the subgroup level and the pride level, with decisions representing putatively fitness-enhancing strategies. Individuals were typically shifting between having few strong connections and having many weaker connections depending on prevailing ecological conditions, with prey abundance, dispersion and body size having the greatest impact on decisions about splitting into subgroups. The maintenance of connections within prides and subgroups in the face of ecological change suggests that the fission-fusion nature of lion prides might be essential for the long-term maintenance of social connections even when short-term conditions do not allow them. More broadly, our study reveals how fission-fusion dynamics and ecological factors can simultaneously have an effect on animals across multiple levels of sociality.

中文翻译：

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生态因素对非洲狮社会结构精细尺度格局的影响

环境变化可以通过改变分组的价值来影响个体与其他个体互动的程度。众所周知，许多物种可以形成和解散群体，通常是对资源的分布和丰富程度做出反应。虽然之前的研究表明资源会影响动物群体的大尺度结构，但在它们是否影响群体内个体之间的精细关联模式方面，知识差距仍然存在。我们量化非洲狮的关联模式，同时监测猎物的丰度和分布。我们测试了社会和生态因素，包括个体特征（年龄、性别、生殖状态）的相似性和猎物的可用性（猎物的丰度、分散、群体大小和体型）如何影响非洲狮的自尊心社会结构。我们发现，关于伙伴的个人决定取决于资源的可用性，当猎物群稀少、聚集或体型庞大时，个体在所有成员之间平等地关联，而当猎物群丰富、分散时，则更专门地关联（在首选伙伴的子群中）或体型较小。当狮群分裂成亚群时，狮子群中的个体似乎通过调节它们与同种的连接强度和密度来缓冲猎物可用性的变化。当猎物群较大时，亚群内个体之间的联系强度和密度较大，而当猎物群分散或体型较大时，则较低。我们的研究结果表明，个体狮子会在亚群层面和骄傲层面做出社会决策，与代表假定健身增强策略的决定。根据普遍的生态条件，个体通常在很少有强联系和有很多较弱联系之间转换，猎物的丰度、分布和体型对分裂成亚群的决定影响最大。面对生态变化，狮群和亚群内部联系的维持表明，狮群的裂变融合性质可能对于长期维持社会联系至关重要，即使短期条件不允许。更广泛地说，我们的研究揭示了裂变融合动力学和生态因素如何同时对多个社会层次的动物产生影响。根据普遍的生态条件，个体通常在很少有强联系和有很多较弱联系之间转换，猎物的丰度、分布和体型对分裂成亚群的决定影响最大。面对生态变化，狮群和亚群内部联系的维持表明，狮群的裂变融合性质可能对于长期维持社会联系至关重要，即使短期条件不允许。更广泛地说，我们的研究揭示了裂变融合动力学和生态因素如何同时对多个社会层次的动物产生影响。根据普遍的生态条件，个体通常在很少有强联系和有很多较弱联系之间转换，猎物的丰度、分布和体型对分裂成亚群的决定影响最大。面对生态变化，狮群和亚群内部联系的维持表明，即使在短期条件不允许的情况下，狮群的裂变融合性质对于长期维持社会联系也可能是必不可少的。更广泛地说，我们的研究揭示了裂变融合动力学和生态因素如何同时对多个社会层次的动物产生影响。分散和体型对分裂成亚群的决定影响最大。面对生态变化，狮群和亚群内部联系的维持表明，狮群的裂变融合性质可能对于长期维持社会联系至关重要，即使短期条件不允许。更广泛地说，我们的研究揭示了裂变融合动力学和生态因素如何同时对多个社会层次的动物产生影响。分散和体型对分裂成亚群的决定影响最大。面对生态变化，狮群和亚群内部联系的维持表明，狮群的裂变融合性质可能对于长期维持社会联系至关重要，即使短期条件不允许。更广泛地说，我们的研究揭示了裂变融合动力学和生态因素如何同时对多个社会层次的动物产生影响。面对生态变化，狮群和亚群内部联系的维持表明，狮群的裂变融合性质可能对于长期维持社会联系至关重要，即使短期条件不允许。更广泛地说，我们的研究揭示了裂变融合动力学和生态因素如何同时对多个社会层次的动物产生影响。面对生态变化，狮群和亚群内部联系的维持表明，狮群的裂变融合性质可能对于长期维持社会联系至关重要，即使短期条件不允许。更广泛地说，我们的研究揭示了裂变融合动力学和生态因素如何同时对多个社会层次的动物产生影响。