RAW DATA from Variability in individual activity bursts improves ant foraging success

Using experimental and computational methods, we study the role of behavioural variability in activity bursts (or temporal activity patterns) for individual and collective regulation of foraging in <i>A. senilis</i> ants. First, foraging experiments were carried out under special conditions (low densities of ants and food and absence of external cues or stimuli) where individual-based strategies are most prevalent. By using marked individuals and recording all foraging trajectories, we were then able to precisely quantify behavioural variability among individuals. Our main conclusions are that (i) variability of ant trajectories (turning angles, speed, etc.) is low compared with variability of temporal activity profiles, and (ii) this variability seems to be driven by plasticity of individual behavioural through time, rather than the presence of fixed behavioural stereotypes or specialists within the group. The statistical measures obtained from these experimental foraging patterns are then used to build a general agent-based model (ABM) which includes the most relevant properties of ant foraging under natural conditions, including recruitment through pheromone communication. Using the ABM, we are able to provide computational evidence that the characteristics of individual variability observed in our experiments can provide a functional advantage (in terms of foraging success) to the group; thus, we propose the biological basis underpinning our observations. Altogether, our study reveals the potential utility of experiments under simplified (laboratory) conditions for understanding information-gathering in biological systems.

本研究结合实验与计算手段，探究了活动爆发（亦称时序活动模式）中的行为变异性对A. senilis蚂蚁觅食行为的个体与群体调控作用。首先，本研究在特殊实验条件下开展觅食实验：蚂蚁与食物密度均较低，且无外部线索或刺激，此时基于个体的觅食策略占据主导地位。通过对蚂蚁个体进行标记并记录全部觅食轨迹，我们得以精准量化个体间的行为变异性。本研究的核心结论包括两点：其一，与时序活动模式的变异性相比，蚂蚁轨迹（转向角度、移动速度等）的变异性较低；其二，此类变异性似乎源于个体行为随时间产生的可塑性，而非群体内存在固定行为刻板模式或特化个体。本研究将从实验觅食模式中提取的统计指标，用于构建通用智能体模型（agent-based model, ABM），该模型涵盖了自然条件下蚂蚁觅食的核心特征，包括通过信息素通讯完成的招募行为。借助该智能体模型，我们得以提供计算证据，证明实验中观测到的个体变异性特征能够为蚁群带来觅食成功率层面的功能优势；据此，我们提出了支撑本研究观测结果的生物学基础。综上，本研究揭示了简化（实验室）条件下的实验在理解生物系统信息获取机制方面的潜在应用价值。