Locomotory rates of worms on different bacterial strains. Well-fed C. elegans (A), Pristionchus pacificus (B) and Panagrellus redivivus (C) were tested for locomotion on five different bacterial strains vs. no bacteria. Histograms show mean ± SEM locomotion frequency measured using an automated tracker. Locomotion frequencies for each nematode species were compared using 1-factor ANOVA followed by planned pairwise comparisons. For each species, there were statistically significant differences among the groups (P << 0.001). We performed planned pairwise comparisons of 'no bacteria' vs. each other bacterial strain. Statistically significant differences in pairwise comparisons with 'no food' are indicated over the each column compared [* - P < 0.05, ** - P < 0.01, *** - P < 0.001]. Number of worms scored per column: C. elegans (n = 28-50), P. pacificus (n = 13-16), P. redivivus (n = 11-21).