Data from: Task-switching is associated with temporal delays in Temnothorax rugatulus ants

The major evolutionary transitions often result in reorganization of biological systems, and a component of such reorganization is that individuals within the system specialize on performing certain tasks, resulting in a division of labor. Although the traditional benefit of division of labor is thought to be a gain in work efficiency; one alternative benefit of specialization is avoiding temporal delays associated with switching tasks. While models have demonstrated that costs of task switching can drive the evolution of division of labor, little empirical support exists for this hypothesis. We tested whether there were task switching costs in Temnothorax rugatulus. We recorded the behavior of every individual in 44 colonies and used this dataset to identify each instance where an individual performed a task, spent time in the interval (i.e. inactive, wandering inside, self-grooming), and then performed a task again. We compared the interval time where an individual switched task type between that first and second bout of work to instances where an individual performed the same type of work in both bouts. In certain cases we find that the interval time was significantly shorter if individuals repeated the same task. We find this time cost for switching to a new behavior in all active worker groups, i.e. independently of worker specialization. These results suggest that task-switching costs may select for behavioral specialization.

重大进化转变（major evolutionary transitions）通常会引发生物系统的重组，而此类重组的一个核心表现为系统内的个体特化于执行特定任务，进而形成劳动分工（division of labor）。尽管传统观点认为劳动分工的核心益处在于提升工作效率，但特化行为的另一项潜在优势则是规避与任务切换（task switching）相关的时间延迟。尽管已有模型证实任务切换成本可推动劳动分工的演化，但目前针对该假说的实证支持仍较为匮乏。本研究以红扁胸切叶蚁（Temnothorax rugatulus）为对象，检验其是否存在任务切换成本。我们记录了44个蚁群中所有个体的行为，并依托该数据集识别出所有符合以下特征的事件：个体先执行一项任务，随后进入间隔状态（即静止、巢内漫游、自我理毛），之后再次执行任务。我们将个体在两次任务执行间隙切换任务类型时的间隔时长，与个体在两次任务中均执行同一类型任务时的间隔时长进行了对比。在部分实验场景中，我们发现若个体重复执行同一任务，其间隔时长会显著更短。我们在所有活跃工蚁群体中均发现了切换至新行为时存在的时间成本，且该成本不受工蚁特化程度的影响。上述结果表明，任务切换成本或可成为选择压力，推动行为特化的演化。