Interaction ruling animal collective behavior depends on topological rather than metric distance: Evidence from a field study
Interaction ruling animal collective behavior depends on topological rather than metric distance: Evidence from a field study
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DOI：
10.1073/pnas.0711437105
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发表时间：
2008-01-29
影响因子：
11.1
通讯作者：
Zdravkovic, V.
中科院分区：
文献类型：
--
作者：
Ballerini, M.;Calbibbo, N.;Zdravkovic, V.
数值模型表明，动物的集体行为可能源于个体之间相互作用的简单局部规则。然而，人们对这种相互作用的性质知之甚少，因此模型和理论大多依赖于先验假设。通过重建的三维位置的个别鸟类在空中的几千名成员的羊群，我们表明，相互作用并不依赖于度量距离，因为大多数目前的模型和理论假设，而是在拓扑距离。事实上，我们发现每只鸟平均与固定数量的邻居（6到7个）互动，而不是与固定度量距离内的所有邻居互动。我们认为，拓扑相互作用是必不可少的，以保持一个群体的凝聚力对大的密度变化所造成的外部扰动，通常捕食。我们支持这一假设的数值模拟，表明拓扑相互作用赠款显着更高的凝聚力的聚合相比，一个标准的度量。
Numerical models indicate that collective animal behavior may emerge from simple local rules of interaction among the individuals. However, very little is known about the nature of such interaction, so that models and theories mostly rely on aprioristic assumptions. By reconstructing the three-dimensional positions of individual birds in airborne flocks of a few thousand members, we show that the interaction does not depend on the metric distance, as most current models and theories assume, but rather on the topological distance. In fact, we discovered that each bird interacts on average with a fixed number of neighbors (six to seven), rather than with all neighbors within a fixed metric distance. We argue that a topological interaction is indispensable to maintain a flock's cohesion against the large density changes caused by external perturbations, typically predation. We support this hypothesis by numerical simulations, showing that a topological interaction grants significantly higher cohesion of the aggregation compared with a standard metric one.