Laboratoire de Physique et Mécanique des Milieux Hétérogènes (PMMH), CNRS UMR 7636, ESPCI Paris-PSL Research University, Sorbonne Université-Université Paris Cité, 10 rue Vauquelin, 75005, Paris, France.
Commun Biol. 2023 May 31;6(1):585. doi: 10.1038/s42003-023-04861-8.
We experimentally investigate the role of illumination on the collective dynamics of a large school (ca. 50 individuals) of Hemigrammus rhodostomus. The structure of the group, defined using two order parameters, is quantified while progressively altering the visual range of the fish through controlled cycles of ambient light intensity. We show that, at low light levels, the individuals within the group are unable to form a cohesive group, while at higher illuminance the degree of alignment of the school correlates with the light intensity. When increasing the illuminance, the school structure is successively characterized by a polarized state followed by a highly regular and stable rotational configuration (milling). Our study shows that vision is necessary to achieve cohesive collective motion for free swimming fish schools, while the short-range lateral line sensing is insufficient in this situation. The present experiment therefore provides new insights into the interaction mechanisms that govern the emergence and intensity of collective motion in biological systems.
我们通过实验研究了光照对一大群（约 50 条）Hemigrammus rhodostomus 集体动力学的影响。通过控制环境光照强度的周期性变化，我们使用两个序参量来量化群体的结构，并定量研究鱼类的视觉范围逐渐改变时的群体结构。结果表明，在低光照水平下，群体中的个体无法形成一个有凝聚力的群体，而在较高的光照度下，群体的排列程度与光强度相关。当增加光照度时，群体结构依次表现为极化状态，随后是高度规则和稳定的旋转配置（磨碎）。我们的研究表明，对于自由游动的鱼群来说，视觉是实现凝聚集体运动所必需的，而在这种情况下，短程侧线感觉是不够的。因此，本实验为控制生物系统中集体运动出现和强度的相互作用机制提供了新的见解。
