Flagellates are the primary consumers of bacteria and picophytoplankton in aquatic environments. They use their beating flagellum to swim and create a feeding current from which they harvest prey, but the movement of the flagellum also attracts the flagellates flow-sensing predators. Using computational fluid dynamics, we examined how the waveforms of the flagella of various model organisms solve the foraging-propulsion-stealth trade-off. In autotrophic flagellates that utilize flagella only for propulsion, there is no design conflict between propulsion and stealth. However, in phagotrophic flagellates, the waveform that is optimal for foraging conflicts with stealth and propulsion optimization, implying that efficient foragers will run higher predation risks, and vice versa. The highly diverse flagellar arrangements found among phagotrophic flagellates may represent different solutions to this trade-off, which thus is a source of functional diversity among flagellates.
Read the paper here: https://link.aps.org/doi/10.1103/PRXLife.1.013002
Asadzadeh S. S., Walther J. H., Kiørboe T., Conflicting roles of flagella in planktonic protists: Propulsion, resource acquisition, and stealth. PRX Life, 1, 013002 (2023)