Evolution of stickiness with modified sticking scheme. Here, we reproduce Figure 5 in the text with the modified assumption that a sticky and nonsticky microbe stick together when coming into contact. For mean velocity and stickiness versus race duration (a), over reset cycles (b) and versus drag factor γ (c), we see no significant quantitative difference. For the mean velocity and stickiness versus sticking cost (d), we see a quantitative difference but observe the same qualitative behaviour. Here since some nonsticky microbes can still hitchhike when coming into contact with sticky ones, the critical cost where the population evolves to lose stickiness is now at a larger value. The transition from sticking to nonsticking is also more gradual compared to the case where sticky and nonsticky microbes do not stick. Results are given by averaging over all microbes over 5 runs. Shaded regions correspond to one standard deviation from the mean