The amount of attractant encountered with time, normalised by maximum attractant concentration, for different responses and parameter values, with d = 0.001: adaptive response is indicated in orange ( β = 0.01) or red ( β = 100.0), linear response in blue ( β = 0.01). Results are presented for both low sensitivity (λ = 1.7, where adaptive and linear responses display similar performances, thin lines) and high sensitivity (λ = 100.0, thick lines). The linear response achieves very little chemotaxis with large values of β. The optimal hybrid mixture for λ
= 1.7 (λ
= 1.1, λ
= 0.6) is shown as a thin green line. α0 = 0.01 for all curves. Resultant bacteria distributions for some of these selected responses are shown in Figure 2.