Adaptive gyration mechanism in fan worm gill filaments for enhanced filter-feeding efficiency

• Fan worm gill filaments passively gyrate via V-shaped section and unbalanced torsion. • Passive gyration increases particle capture efficiency by 141% on average. • Gill filaments achieve efficient filtration, showing physical intelligence. Efficient filter-feeding in varying aquatic flows necessitates specialized adaptations in morphology and motion. Notably, the specialized gill filaments of a fan worm ( Annelida: Sabellidae) exhibit remarkable motion flexibility, enabling efficient filter-feeding in variable flow conditions, which present a physical/mechanical intelligence in the ocean environment. These soft gill filaments, characterized by their V-shaped cross-section, can passively gyrate in response to water flow, a behavior driven by fluid-induced unbalanced torsion. Two paradigms of robotic gill filaments (RoboGFs) were created, demonstrating that such passive adaptation enhances the particle capture rate by an average of 141% compared to a completely rigid design. These findings may inspire the development of efficient particle-capturing devices suitable for use in unpredictable aquatic environments.