Mean (± 95% CI) alpha Faith’s bacterial diversity (phylogenetic diversity metric) across water treatments for samples from the guts of (a) tadpoles and (b) adults. Water treatment did not significantly affect bacterial diversity of tadpoles (GLM, atrazine: χ2 = 1.85, df = 1, P = 0.17, metyrapone: χ2 = 0.66, df = 1, P = 0.42, interaction: χ2 = 2.19, df = 1, P = 0.14), but adults exposed to metyrapone as tadpoles had significantly higher bacterial diversity compared to adults that were not exposed to metyrapone (GLMM, atrazine: χ2 = 0.20, df = 1, P = 0.65, metyrapone: χ2 = 4.56, df = 1, P = 0.03, interaction: χ2 = 0.54, df = 1, P = 0.47).