Fig. 3: Microswimmer dynamics for different number of beads N.
a, b Stroke-averaged cennter of mass (COM) velocity, \(\bar{v}\), of different type A and B microswimmers, respectively, corresponding to their fitness score when optimized independently with evolutionary algorithms for N = 3 to N = 100 beads (see also Fig. 1c). Insets show COM trajectories, and \(({F}_{1}^{a},{F}_{3}^{a})\)- and (l1, l2)-phase-space plots for N = 3 (see blue circles). Typical bead-specific coordinate- (c, d) and force-trajectories (e, f) of an (N = 15)-bead type A and an (N = 100)-bead type B microswimmer, respectively (the examples, see red circles in (a, b), are chosen for illustrative purposes and are representative for all investigated N for both type A and B policies). See also Supplementary Movies 1-3. Insets in (c, d) detail the corresponding COM trajectories. For type A microswimmers (a, c, e), periodic localized waves of arm strokes travel through the body. In contrast, (b, d, f), large-scale collective body contractions allow large type B microswimmers to propagate much faster. Coordinate trajectories are normalized by the reference arm length L0 in the insets of (a, b), and by the total sum of the reference arm lengths LB = L0 × (N − 1) in (c–f).
