Figure 3.

Shared effector host immune responses tend to be more robust than independent effector host immune responses. Host signalling network robustness was measured as the mean absolute difference between immune effector activity in intact and knockout hosts, using the most common hosts from the end of independent evolution simulations as the population of intact hosts. Higher values indicate networks were less robust; see §2d for detailed methods. The y-axis shows the mean absolute difference between the knockout immune response and the intact host immune response. The columns indicate the resource availability of the simulations intact hosts evolved in. Black/red lines are mean change in effector abundance following knockout. Within a resource condition, independence of samples was determined using a Kruskal–Wallis non-parametric ANOVA and if significant differences were detected, multiple comparisons were carried out using pairwise Mann–Whitney U tests. Groups that share a letter are not significantly different from each other and letters are re-used between resource conditions.