Effect of varying Michaelis constant, ak. (A) Dependence of expansion speed on the chemotactic sensitivity, , for different values of ak and . Solid lines indicate analytical solutions for corresponding best fit values of η, and markers denote the numerical solutions. Results for , and are shown in yellow, red, and blue, respectively. (B) Dependence of the expansion speed on model parameter ak. The numerical solutions obtained for are represented by yellow triangles, and the analytic solution found in Eq. 21 for is shown by the red line. Parameters have the default values from SI Appendix, Table S1, unless specified.