a, Experimental design in which Conv flies (Canton-S) were treated with antibiotics (ABX, black arrow) for 3 days following eclosion. All flies were subsequently placed on irradiated media either without supplementation or treated with L.b CFS (green arrows) for 3 days. 1 hr. prior to and during testing flies were either exposed to 27˚C (red line) to facilitate thermogenetic activation or kept at 20˚C (blue line). b – h, Average speed of flies previously treated with antibiotics and subsequently left untreated (ABX) or administered with L.b CFS for 3 days prior to testing. (b) UAS: ABX, n = 15; L.b CFS, n = 14; GAL4: ABX, n = 24; L.b CFS, n = 20; GAL4>UAS (27°C): ABX, n = 14; L.b CFS, n = 9; GAL4>UAS (20°C): ABX, n = 16; L.b CFS, n = 11. (c) UAS: ABX, n = 24; L.b CFS, n = 24; GAL4: ABX, n = 24; L.b CFS, n = 23; GAL4>UAS (27°C): ABX, n = 25; L.b CFS, n = 26; GAL4>UAS (20°C): ABX, n = 19; L.b CFS, n = 19. (d) UAS: ABX, n = 26; L.b CFS, n = 18; GAL4: ABX, n = 36; L.b CFS, n = 24; GAL4>UAS (27°C): ABX, n = 53; L.b CFS, n = 23; GAL4>UAS (20°C): ABX, n = 21; L.b CFS, n = 7. (e) UAS: ABX, n = 34; L.b CFS, n = 26; GAL4: ABX, n = 34; L.b CFS, n = 28; GAL4>UAS (27°C): ABX, n = 10; L.b CFS, n = 17; GAL4>UAS (20°C): ABX, n = 17; L.b CFS, n = 13. (f) UAS: ABX, n = 36; L.b CFS, n = 30; GAL4: ABX, n = 40; L.b CFS, n = 31; GAL4>UAS (27°C): ABX, n = 19; L.b CFS, n = 17; GAL4>UAS (20°C): ABX, n = 14; L.b CFS, n = 8. (g) UAS: ABX, n = 21; L.b CFS, n = 12; GAL4: ABX, n = 28; L.b CFS, n = 24; GAL4>UAS (27°C): ABX, n = 24; L.b CFS, n = 20; GAL4>UAS (20°C): ABX, n = 16; L.b CFS, n = 15. (h) UAS: ABX, n = 31; L.b CFS, n = 20; GAL4: ABX, n = 31; L.b CFS, n = 29; GAL4>UAS (27°C): ABX, n = 16; L.b CFS, n = 17; GAL4>UAS (20°C): ABX, n = 18; L.b CFS, n = 14. Box-and-whisker plots show median and IQR. * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001. Specific P values are in the Supplementary Material. Mann-Whitney U post-hoc tests following a Two-way ANOVA were used for statistical analysis. Data are representative of at least 2 independent trials for each experiment.