Department of Biology and Mountain Lake Biological Station, University of Virginia, Charlottesville, VA, USA.
Biology Department, Swarthmore College, Swarthmore, PA, USA.
J Anim Ecol. 2022 Apr;91(4):895-907. doi: 10.1111/1365-2656.13684. Epub 2022 Mar 11.
Social interactions drive many important ecological and evolutionary processes. It is therefore essential to understand the intrinsic and extrinsic factors that underlie social patterns. A central tenet of the field of behavioural ecology is the expectation that the distribution of resources shapes patterns of social interactions. We combined experimental manipulations with social network analyses to ask how patterns of resource distribution influence complex social interactions. We experimentally manipulated the distribution of an essential food and reproductive resource in semi-natural populations of forked fungus beetles Bolitotherus cornutus. We aggregated resources into discrete clumps in half of the populations and evenly dispersed resources in the other half. We then observed social interactions between individually marked beetles. Half-way through the experiment, we reversed the resource distribution in each population, allowing us to control any demographic or behavioural differences between our experimental populations. At the end of the experiment, we compared individual and group social network characteristics between the two resource distribution treatments. We found a statistically significant but quantitatively small effect of resource distribution on individual social network position and detected no effect on group social network structure. Individual connectivity (individual strength) and individual cliquishness (local clustering coefficient) increased in environments with clumped resources, but this difference explained very little of the variance in individual social network position. Individual centrality (individual betweenness) and measures of overall social structure (network density, average shortest path length and global clustering coefficient) did not differ between environments with dramatically different distributions of resources. Our results illustrate that the resource environment, despite being fundamental to our understanding of social systems, does not always play a central role in shaping social interactions. Instead, our results suggest that sex differences and temporally fluctuating environmental conditions may be more important in determining patterns of social interactions.
社会互动驱动着许多重要的生态和进化过程。因此，理解构成社会模式的内在和外在因素至关重要。行为生态学领域的一个中心原则是，预期资源的分布决定了社会互动的模式。我们将实验操作与社会网络分析相结合，以了解资源分布模式如何影响复杂的社会互动。我们在叉突菌象鼻虫（Bolitotherus cornutus）的半自然种群中，对一种重要的食物和生殖资源进行了实验性操纵，将资源集中在一半种群中的离散团块中，而将资源在另一半种群中均匀分散。然后，我们观察了个体标记的甲虫之间的社会互动。在实验进行到一半时，我们在每个种群中反转了资源分布，从而可以控制我们的实验种群之间的任何人口统计学或行为差异。在实验结束时，我们比较了两种资源分布处理之间个体和群体社会网络特征。我们发现资源分布对个体社会网络位置有统计学上显著但数量上较小的影响，并且没有检测到对群体社会网络结构的影响。在聚集资源的环境中，个体连接性（个体强度）和个体结群性（局部聚类系数）增加，但这种差异仅解释了个体社会网络位置变化的很小一部分。个体中心性（个体中间度）和整体社会结构的度量（网络密度、平均最短路径长度和全局聚类系数）在资源分布差异很大的环境中没有差异。我们的研究结果表明，尽管资源环境是我们理解社会系统的基础，但它并不总是在塑造社会互动中发挥核心作用。相反，我们的研究结果表明，性别差异和随时间波动的环境条件可能更重要，决定了社会互动的模式。
