FIG 4.

Effects of different concentrations of glyphosate and of tylosin on Snodgrassella abundance in the guts of laboratory-raised honey bees. (A) Bees at 1 day postemergence were treated with glyphosate or tylosin for 20 days (early exposure). From left to right, box plots show Snodgrassella 16S rRNA copy numbers in the guts of control bees, of 0.01, 0.04, 0.07, 0.1, and 1.0 mM glyphosate-fed bees, and of 0.1 mM tylosin-fed bees sampled at days 5 (n = 15 each), 10 (n = 15 each), 15 (n = 15, 15, 15, 15, 15, 14, and 15), and 20 (n = 10, 10, 11, 11, 11, 11, and 10) after the start of treatment. (B) Bees at 5 days postemergence were treated with glyphosate or tylosin for 15 days (late exposure). From left to right, box plots show Snodgrassella 16S rRNA copy numbers in the guts of control bees, of 0.01, 0.04, 0.07, 0.1, and 1.0 mM glyphosate-fed bees, and of 0.1 mM tylosin-fed bees sampled at days 5 (n = 13, 13, 13, 13, 13, 13, and 12), 10 (n = 12 each), and 15 (n = 12 each) after the start of treatment. Groups with different letters are statistically significantly different (P < 0.05, Kruskal-Wallis test followed by Dunn’s multiple-comparison test) (Table S1C).