Departamento de Física, Universidade Estadual de Maringá, Maringá, PR, 87020-900, Brazil.
U.S. Geological Survey, Columbia Environmental Research Center, 4200 New Haven Road, Columbia, MO, 65201, USA.
Sci Rep. 2022 Oct 25;12(1):17873. doi: 10.1038/s41598-022-22515-3.
Despite significant efforts devoted to understanding the underlying complexity and emergence of collective movement in animal groups, the role of different external settings on this type of movement remains largely unexplored. Here, by combining time series analysis and complex network tools, we present an extensive investigation of the effects of shady environments on the behavior of a fish species (Silver Carp Hypophthalmichthys molitrix) within earthen ponds. We find that shade encourages fish residence during daylight hours, but the degree of preference for shade varies substantially among trials and ponds. Silver Carp are much slower and exhibit lower persistence in their speeds when under shade than out of it during daytime and nighttime, with fish displaying the highest persistence degree and speeds at night. Furthermore, our research shows that shade affects fish schooling behavior by reducing their polarization, number of interactions among individuals, and the stability among local neighbors; however, fish keep a higher local degree of order when under shade compared to nighttime positions.
尽管人们在理解动物群体中集体运动的内在复杂性和涌现方面做出了巨大努力，但不同外部环境对这种运动的影响在很大程度上仍未得到探索。在这里，我们通过结合时间序列分析和复杂网络工具，对鱼类（鲢鱼 Hypophthalmichthys molitrix）在土塘中的行为在荫蔽环境下的影响进行了广泛的研究。我们发现，荫蔽环境会促使鱼类在白天停留，但在不同的试验和池塘中，鱼类对荫蔽环境的偏好程度有很大差异。与白天和夜间在无荫蔽环境下相比，鱼类在荫蔽环境下的速度要慢得多，且速度的持久性也较低，而在夜间，鱼类的持久性和速度最高。此外，我们的研究表明，荫蔽环境通过减少鱼类的极化、个体之间的相互作用数量以及局部邻居之间的稳定性来影响鱼类的群体行为；然而，与夜间位置相比，鱼类在荫蔽环境下保持着更高的局部有序度。
