It's better to forget: exploring the role of stigmergy decay in navigation behavior

Stigmergy is an indirect mechanism of coordination where an action alters the environment and the changed environment, in turn, alters the likelihood of future actions. Pheromone-marker-based stigmergy is the most common form of stigmergy used in social insect groups. The ant species Monomorium pharaonis produces pheromones that decay after several minutes, whereas Atta columbica ants produce pheromones that persist for several years. The respective transience and permanence of these ants’ foraging paths is thought to be related to their pheromones’ volatility. Several mathematical and computational models have demonstrated that relatively moderate pheromone decay rates are correlated with increased foraging success in stigmergic agents. However, the implications of pheromone volatility on the evolution of navigation behavior are not well-studied. Here we use digital agent-based evolution to show that moderate pheromone decay rates correspond to an increase in the extent to which agent foraging behavior relies on stigmergic cues. This result suggests that the properties of an organism’s pheromones play a vital role in the organism’s evolutionary trajectory, driving some towards, and others away from, stigmergic foraging strategies. These results help shed light on how elements of an organism’s environment, such as the stability of its food source, relate to the properties of that organism’s pheromones. Understanding the evolution of stigmergic group coordination strategies, an instance of collective cognition, provides a foundation for addressing the larger questions surrounding the evolution of intelligence.

觅食信息素标记的群居昆虫群体中最常见的协同机制为觅食信息素标记的群居昆虫群体。例如，法老蚁（Monomorium pharaonis）产生的信息素在几分钟内就会衰减，而火蚁（Atta columbica）产生的信息素则可持久数年。这些蚂蚁觅食路径的短暂性与持久性被认为与其信息素的挥发性有关。众多数学和计算模型已证实，相对适度的信息素衰减速率与觅食协同个体的觅食成功率呈正相关。然而，关于信息素挥发性对导航行为演化的影响研究尚不充分。在本研究中，我们运用基于数字智能体的进化模型表明，适度的信息素衰减速率与智能体觅食行为对觅食协同线索的依赖程度增加相对应。此结果暗示，生物体信息素的性质在其进化轨迹中扮演着至关重要的角色，驱使某些生物趋向于、而另一些则远离觅食协同策略。这些研究结果有助于阐明生物体环境要素，如食物源的稳定性，与该生物体信息素性质之间的关联。理解群居协同策略的进化，即集体认知的实例，为探讨围绕智能体进化的大问题提供了基础。