Transitions between synchronization states mediated by basal body coupling. Radial dynamics are again fast compared to phase dynamics (). (a) Steady state as a function of ky for various ciliary spacings (, 20, 25, 35, 50, ). Numerical solutions (smooth, coloured) are shown alongside analytical predictions to leading order (dashed, black) and second order in (dashed, coloured). The transition zone boundaries are quantified by (red crosses) and (blue crosses), respectively. (b) These are shown as a function of l, together with leading order (black) and second order in (coloured) analytical predictions. (Online version in colour.)