Polygonal motion and adaptable phototaxis via flagellar beat switching in Euglena gracilis

摘要: Biological microswimmers exhibit versatile strategies for sensing and navigating their environment, e.g., run-and-tumble curvature modulation. Here we report a striking behavior of Euglena gracilis, where cells swim in polygonal trajectories due to exposure increasing light intensities. While smoothly curved are common microswimmers, such quantized ones have not been reported previously. This emerges from periodic switching between the flagellar beating patterns helical swimming spinning behaviors. We develop experimentally validate biophysical model that describes phase relationship eyespot, cell orientation, detection, cellular reorientation, accounts all three behavioral states. Coordinated these behaviors allows ballistic, superdiffusive, diffusive, or subdiffusive motion (i.e., tuning diffusion constant over 3 orders magnitude) enables navigation structured fields, edge avoidance gradient descent. feedback-control links multiple system scales (flagellar beats, behaviors, phototaxis strategies) with implications other natural synthetic microswimmers.