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arXiv · 2503.21396

Forces and symmetry breaking of a living meso-swimmer

Rafael A. Lara·N. Sharadhi·Anna A. L. Huttunen·Lotta Ansas·Ensio J. G. Rislakki·Guilherme M. Bessa·Matilda Backholm
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Abstract

Swimming is ubiquitous in nature and crucial for the survival of a wide range of organisms. The physics of swimming at the viscosity-dominated microscale and inertia-dominated macroscale is well studied. However, in between lies a complicated mesoscale with swimmers affected by non-linear and time-dependent fluid mechanics. The intricate motility strategies, combined with complex and periodically changing body shapes add extra challenges for accurate meso-swimming modelling. Here, we have further developed the micropipette force sensor to directly probe the swimming forces of the meso-organism Artemia. Through deep neural network-based image analysis, we show how Artemia achieves an increased propulsive force by increasing its level of time-reversal symmetry breaking. We present a universal force-based scaling law for a wide range of micro- to meso-organisms with different body shapes, swimming strategies, and level of inertia at the mesoscale. These results capture fundamental aspects of biological meso-swimming dynamics and provide guidance for future biomimicking meso-robot designs.

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Rafael A. Lara, N. Sharadhi, Anna A. L. Huttunen, Lotta Ansas, Ensio J. G. Rislakki, Guilherme M. Bessa, Matilda Backholm. 2026-01-28. Forces and symmetry breaking of a living meso-swimmer. https://doi.org/10.1038/s42005-025-02486-3

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