Figure 3: Simulation and empirical data on defector fitness under increasing defector inhibition.

(a) Simulation of defector payoff as a function of defector initial frequency and presence of compounds specifically inhibiting defectors. A positive relative payoff (blue region) indicates higher fitness of the defector, whereas a negative one indicates higher fitness of the cooperator (red region). (b) Empirical data showing the fitness of the model defector Pseudomonas fluorescens CHA0ΔgacS as a function of its initial frequency and its mean genetic distance to the community of cooperating bacteria. A fitness value >1 (blue region) indicates faster growth of the defector, whereas a value between 0 and 1 (red region) indicates faster growth of the cooperator. The isoclines correspond to the polynomial surface regression reported in Table 1 (R²=0.56, P<0.0001). Grey circles represent the individual communities.