Fig. 4
Stochastic diversification of evolved replicate populations can be greater on an alternative surface than on their selective surface and varies across treatments. Within-treatment diversification index (Ix) for swarming rates. Ix values here represent the average divergence among multiple independently evolved pairs of strains that each descended from the same ancestor and evolved in the same environment. Each individual point indicates the diversification index of a unique pair. **p < 0.01 for significant difference in a student t-test. Error bars show 95% confidence intervals