Emergent Collective Locomotion in an Active Polymer Model of Entangled Worm Blobs
Emergent Collective Locomotion in an Active Polymer Model of Entangled Worm Blobs
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DOI：
10.3389/fphy.2021.734499
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发表时间：
2021-09-30
影响因子：
3.1
通讯作者：
Peleg, Orit
中科院分区：
文献类型：
--
作者：
Nguyen, Chantal;Ozkan-Aydin, Yasemin;Peleg, Orit
许多蠕虫和节肢动物物种形成物理连接的聚集体，其中个体之间的相互作用产生了新兴的宏观动态和功能，从而增强了集体生存。特别是一些水生蠕虫，如加州黑虫（Lumbriculus variegatus），会将身体缠绕成致密的斑点，以保护自己免受外部压力的影响，并在干燥条件下保持水分。受最近揭示黑虫斑点中紧急运动的实验的启发，我们通过将每条蠕虫建模为自驱动布朗聚合物来研究集体蠕虫动力学。尽管我们的模型是二维的，但与真实的三维蠕虫斑点相比，我们演示了模拟斑点如何通过主动运动和环境之间的耦合来共同穿越温度梯度。通过对蠕虫之间的吸引力强度及其定向自推进的大小进行系统参数扫描，我们获得了丰富的相图，该相图揭示了有效的集体运动是通过精细平衡这两个参数之间的结果而出现的。我们的模型将活性丝的物理学带入新的介观和宏观背景，并邀请对细长、半柔性生物体的集体行为进行进一步的理论研究。
Numerous worm and arthropod species form physically-connected aggregations in which interactions among individuals give rise to emergent macroscale dynamics and functionalities that enhance collective survival. In particular, some aquatic worms such as the California blackworm (Lumbriculus variegatus) entangle their bodies into dense blobs to shield themselves against external stressors and preserve moisture in dry conditions. Motivated by recent experiments revealing emergent locomotion in blackworm blobs, we investigate the collective worm dynamics by modeling each worm as a self-propelled Brownian polymer. Though our model is two-dimensional, compared to real three-dimensional worm blobs, we demonstrate how a simulated blob can collectively traverse temperature gradients via the coupling between the active motion and the environment. By performing a systematic parameter sweep over the strength of attractive forces between worms, and the magnitude of their directed self-propulsion, we obtain a rich phase diagram which reveals that effective collective locomotion emerges as a result of finely balancing a tradeoff between these two parameters. Our model brings the physics of active filaments into a new meso- and macroscale context and invites further theoretical investigation into the collective behavior of long, slender, semi-flexible organisms.