(A) Tumble bias vs CW bias for individual wild-type cells (N = 69), plotted separately for different numbers of flagella per cell (Nflag = 1, purple; 2, blue; 3, green; 4, red; 5, cyan). The prediction from the veto model in Equation (1) (dashed lines) does not match the data for cells with multiple flagella (R2 = 0.88, 0.60, 0.41, 0.39 for Nflag = 2, 3, 4, 5). The data were fit (solid lines) to Equation (1), while allowing the number of flagella to be used as a fitting parameter, Neff. Error bars denote SD. (B) Same as (A) for CheY* (open circles, same color code as [A] N = 46 cells). The veto model prediction (dashed lines) matches the data well (R2 = 0.91, 0.97, 0.93, 0.67, 0.98 for Nflag = 1, 2, 3, 4, 5). Fits (solid lines) yield Neff values almost identical to Nflag. (C) Fitted Neff values vs number of flagella per cell for wild-type (black circles) and CheY* (open gray circles) cells. Simulations (described in the text) reproduce the observed trends. (D) Data points from individual wild-type (solid circles) and CheY* (open circles) cells all collapse onto a single line when using Neff from fits to wild-type data in (A) and the actual flagellar number Nflag for CheY* cells in (B). Error bars denote SEM. See ‘Materials and methods’ for more details.