Data_Sheet_1_Scaling of ant colony interaction networks.PDF

In social insect colonies, individuals are physically independent but functionally integrated by interaction networks which provide a foundation for communication and drive the emergence of collective behaviors, including nest architecture, division of labor, and potentially also the social regulation of metabolic rates. To investigate the relationship between interactions, metabolism, and colony size, we varied group size for harvester ant colonies (Pogonomyrmex californicus) and assessed their communication networks based on direct antennal contacts and compared these results with proximity networks and a random movement simulation. We found support for the hypothesis of social regulation; individuals did not interact with each other randomly but exhibited restraint. Connectivity scaled hypometrically with colony size, per-capita interaction rate was scale-invariant, and smaller colonies exhibited higher measures of closeness centrality and edge density, correlating with higher per-capita metabolic rates. Although the immediate energetic cost for two ants to interact is insignificant, the downstream effects of receiving and integrating social information can have metabolic consequences. Our results indicate that individuals in larger colonies are relatively more insulated from each other, a factor that may reduce or filter noisy stimuli and contribute to the hypometric scaling of their metabolic rates, and perhaps more generally, the evolution of larger colony sizes.

在社会性昆虫种群中，个体虽在生理上独立，但通过互动网络实现功能整合——这类网络不仅为信息交流奠定基础，更驱动了集体行为的涌现，包括巢穴构筑、劳动分工，还可能参与代谢速率的社会性调控。为探究互动、代谢与种群规模之间的关联，本研究以美刻收获蚁（Pogonomyrmex californicus）种群为对象，调整其群体规模，基于蚂蚁间直接的触角接触评估其交流网络，并将结果与空间邻近网络以及随机运动模拟结果进行对比。研究结果支持社会性调控假说：蚂蚁个体间的互动并非随机发生，而是表现出互动约束。连接性随种群规模呈亚异速缩放，个体平均互动速率则与种群规模无关；小型种群的接近中心性与边密度指标更高，这与更高的个体平均代谢速率呈正相关。尽管两只蚂蚁互动的即时能量消耗微不足道，但接收并整合社会信息所带来的后续效应，会对代谢产生影响。本研究结果表明，大型种群中的个体彼此间的隔离程度相对更高，这一因素可减少或过滤嘈杂的刺激信号，进而推动代谢速率的亚异速缩放，或许还能从更广泛的层面助力大型种群的演化。