a Ranked substrate fitness curves for ancestral clones (red) and clones pre-adapted with (grey) and without (black) the natural microbial community. Substrates are ranked by the mean value across all clones. Increased separation between responses indicates greater clonal variation, while increased slope differences indicate greater environmental variation. Moreover, differences in rankings (some clones being better on the second substrate than the first), represent instances of resource specialisation. b Pre-adapted populations had higher clonal variance than the LacZ ancestor. c There was no difference in responsiveness between treatments or the LacZ ancestor, indicating no generalist vs. specialist trade-offs due to pre-adaptation (d) Inconsistency was higher in the pre-adapted treatments regardless of the presence of the microbial community, indicating that pre-adaptation resulted in increased resource specialisation. In (b–d), tops and bottoms of the bars represent the 75th and 25th percentiles of the data, the white lines are the medians, and the whiskers extend from their respective hinge to the smallest or largest value no further than 1.5*interquartile range. Points represent the mean value per population.