Fig. 4.

Host specificity of S. alvi strains, as shown by colonization efficiency. Gut bacterial load (CFU) was counted 5 d after oral inoculation. The sample size for each treatment is ≥12. Means, 95% confidence interval of means, and the results of Mann–Whitney U tests (*P < 0.0001) are shown. In competition treatments, strain wkB2^T was coinoculated with strain wkB12 or wkB29 (1:10 ratio in A. mellifera, 10:1 ratio in B. impatiens). Percentage indicates average wkB2^T prevalence in competitions.