Data from: Interspecific social networks promote information transmission in wild songbirds

Understanding the functional links between social structure and population processes is a central aim of evolutionary ecology. Multiple types of interactions can be represented by networks drawn for the same population, such as kinship, dominance or affiliative networks, but the relative importance of alternative networks in modulating population processes may not be clear. We illustrate this problem, and a solution, by developing a framework for testing the importance of different types of association in facilitating the transmission of information. We apply this framework to experimental data from wild songbirds that form mixed-species flocks, recording the arrival (patch discovery) of individuals to novel foraging sites. We tested whether intraspecific and interspecific social networks predicted the spread of information about novel food sites, and found that both contributed to transmission. The likelihood of acquiring information per unit of connection to knowledgeable individuals increased 22-fold for conspecifics, and 12-fold for heterospecifics. We also found that species varied in how much information they produced, suggesting that some species play a keystone role in winter foraging flocks. More generally, these analyses demonstrate that this method provides a powerful approach, using social networks to quantify the relative transmission rates across different social relationships.

解析社会结构与种群过程间的功能关联，是进化生态学（evolutionary ecology）的核心研究目标之一。同一种群内的多种互动类型均可通过社交网络进行可视化表征，例如亲缘关系网络（kinship network）、优势等级网络（dominance network）或亲和社交网络（affiliative network），但不同类型网络在调控种群过程中的相对重要性往往尚不明确。本研究通过构建一套用于检验不同关联类型在促进信息传递中重要性的分析框架，阐明了这一问题及其解决方案。我们将该框架应用于形成混合物种种群鸟群的野生鸣禽实验数据，记录了个体抵达新型觅食位点的情况（即斑块发现事件）。我们检验了种内与种间社交网络是否能够预测新型食物位点相关信息的传播，结果发现二者均对信息传递起到了促进作用。针对知晓信息的个体，每增加一个单位的社交连接，同种个体获取信息的概率提升22倍，异种个体则提升12倍。我们同时发现，不同物种产生的信息量存在差异，这表明部分物种在冬季觅食鸟群中扮演着关键种角色。从更广泛的意义上来说，本分析证明该方法是一种高效的研究手段，可借助社交网络量化不同社交关系间的相对信息传递速率。