Data for: What you have, not who you know: food-enhanced social capital and changes in social behavioural relationships in a non-human primate

Social network position in non-human primates has far-reaching fitness consequences. Critically, social networks are both heterogenous and dynamic, meaning an individual’s current network position is likely to change due to both intrinsic and extrinsic factors. However, our understanding of the drivers of changes in social network position is largely confined to opportunistic studies. Experimental research on the consequences of in situ, controlled network perturbations is limited. Here we conducted a food-based experiment in rhesus macaques to assess whether allowing an individual the ability to provide high-quality food to her group changed her social behavioural relationships. We considered both her social network position across five behavioural networks, as well as her dominance and kin interactions. We found that gaining control over a preferential food resource had far-reaching social consequences. There was an increase in both submission and aggression centrality and changes in the socio-demographic characteristics of her agonistic interaction partners. Further, we found that her grooming balance shifted in her favour as she received more grooming than she gave. Together, these results provide a novel, preliminary insight into how in situ, experimental manipulations can modify social network position and point to broader network-level shifts in both social capital and social power.

Methods
Data collection:

Data were collected on a single group of Rhesus macaques. Behavioural observations were conducted all adult individuals (3+ years) in the group. Affiliative and agonistic interactions were recorded.

Data processing:

Behavioural observations were used to construct a weighted, directed behavioural network for each of the following behaviours, for both baseline and experimental phases separately: (1) dyadic aggressive interactions where aggressive behaviour was met with a clear submissive response, (2) approach – move away interactions, such as displacements, (3) SBT signals in response to peaceful approaches (note: peaceful SBTs may be accompanied by other submissive behaviours including turn away, move away. or rump present), and (4) social grooming interactions. Weighted, undirected networks were constructed for huddling/social contact and proximity interactions. For directed behaviours, indegree, outdegree (the number of adjacent edges to each node), and strength (total number of interactions) were calculated, while degree centrality was calculated for undirected networks.

Dominance ranks were calculated from agonistic interactions for all adult individuals using the Perc package.

非人灵长类动物的社会网络位置对其适合度（fitness）具有深远影响。至关重要的是，社会网络兼具异质性与动态性，即个体当前的网络位置可能因内在与外在因素发生改变。然而，我们对社会网络位置变化驱动因素的认知，目前仍主要局限于偶遇性研究（opportunistic studies），针对原位（in situ）受控网络扰动效应的实验研究则相对匮乏。

本研究以恒河猴（rhesus macaques）为对象开展食物操控实验，旨在探究允许个体为群体提供优质食物，是否会改变其社会行为关系。我们同时分析了该个体在五种行为网络中的社会网络位置，以及其支配关系与亲缘互动情况。结果显示，获得优质食物资源的控制权可产生广泛的社会效应：个体的顺从中心性与攻击中心性均有所提升，其冲突互动伙伴的社会人口统计学特征也出现了变化；此外，该个体的理毛平衡向自身倾斜，即其获得的理毛次数多于付出的理毛次数。综上，本研究为原位实验操控如何改变社会网络位置提供了新颖的初步见解，并揭示了社会资本与社会权力层面更广泛的网络层面变化。

方法
数据收集
研究数据来源于一群恒河猴，我们对群体内所有成年个体（3岁及以上）开展行为观察，记录其亲和行为与冲突行为。

数据处理
基于行为观察数据，我们分别在基线期与实验期，针对以下四类行为构建加权有向行为网络：(1) 伴随明确顺从回应的双向攻击互动；(2) 趋近-逃离互动（如驱离行为）；(3) 针对平和趋近的SBT信号（注：平和SBT可伴随转向、逃离或臀部展露等其他顺从行为）；(4) 社会理毛互动。针对抱团/社会接触与空间亲近互动，则构建加权无向网络。对于有向行为，计算其入度、出度（即每个节点的邻接边数）与强度（互动总次数）；无向网络则计算度中心性。

我们利用Perc软件包，基于所有成年个体的冲突互动数据计算其支配等级。