Collective self-caging of active filaments in virtual confinement

Filamentous cyanobacteria, ancient and prolific phototrophic prokaryotes, significantly contribute to atmospheric carbon fixation via photosynthesis. Their gliding motility, coupled with photophobic responses to light intensity gradients, drives accumulation in favorable light conditions. Our study unveils an intriguing aspect of photosensitivity: the formation of intricate super-filamentous aggregates with collective mechanical capabilities at boundaries of illuminated regions. We investigate the influence of light pattern, especially boundary curvature, on this aggregation process using an agent-based model for active, flexible filaments. While the ecological benefits remain uncertain, this behavior may empower colonies to regulate light exposure and achieve macroscopic movements.