Plot of the fitness landscape of pathogens with fixed host parameters.

Equal pathogen and host concentrations were used. Each blue dot represents one individual with a certain investment into the number of binding sites produced (x-axis location) and a certain fitness (y-axis location, determined by the attack probability solely). The red line represents the goodness of thresholding, which is the relative fitness of a host with attack threshold t, compared to the fitness of a host using the optimal attack threshold t*. Host investment into number of binding sites is arbitrarily fixed to 40% (left) and 60% (right). In the right subfigure, pathogens are restricted to produce a maximum of 90% of host binding sites.