WT Axoneme 1Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_1.zipWT Axoneme 2Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_2.zipWT Axoneme 3Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_3.zipWT Axoneme 4Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_4.zipWT Axoneme 5Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_5.zipWT Axoneme 6Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_6.zipWT Axoneme 7Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_7.zipWT Axoneme 8Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_8.zipWT Axoneme 9Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_9.zipWT Axoneme 10Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii wild type cell (CC-125 wild type mt+137c)WT_10.zipmbo2 Axoneme 1Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_1.zipmbo2 Axoneme 2Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_2.zipmbo2 Axoneme 3Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_3.zipmbo2 Axoneme 4Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_4.zipmbo2 Axoneme 5Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_5.zipmbo2 Axoneme 6Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_6.zipmbo2 Axoneme 7Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_7.zipmbo2 Axoneme 8Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_8.zipmbo2 Axoneme 9Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_9.zipmbo2 Axoneme 10Movie and waveform of a reactivated axoneme, isolated from a Chlamydomonas reinhardtii mbo2 mutant cell (CC-2377 mbo2 mt-)mbo2_10.zip

Cilia and flagella are model systems for studying how mechanical forces control morphology. The periodic bending motion of cilia and flagella is thought to arise from mechanical feedback: dynein motors generate sliding forces that bend the flagellum, and bending leads to deformations and stresses, which feed back and regulate the motors. Three alternative feedback mechanisms have been proposed: regulation by the sliding forces, regulation by the curvature of the flagellum, and regulation by the normal forces that deform the cross-section of the flagellum. In this work, we combined theoretical and experimental approaches to show that the curvature control mechanism is the one that accords best with the bending waveforms of Chlamydomonas flagella. We make the surprising prediction that the motors respond to the time derivative of curvature, rather than curvature itself, hinting at an adaptation mechanism controlling the flagellar beat.