FIG 2.

S. carpocapsae and its bacterial endosymbiont X. nematophila are pathogenic toward D. melanogaster. (A) Survival of D. melanogaster larvae exposed to symbiont S. carpocapsae IJs, axenic S. carpocapsae IJs, or no IJs. All three survival curves are significantly different (P < 0.0001, log rank test). ***, P < 0.001 relative to the no-IJ control (log rank test with Bonferroni correction; n = 6 trials for each condition). (B) Infection (left) and survival (right) of D. melanogaster larvae exposed to either X. nematophila, P. luminescens, E. coli, or no bacteria. All three species of bacteria successfully infected D. melanogaster (left graph) although infection rates were significantly different for each species (P < 0.01, log rank test). ***, P < 0.001 for X. nematophila and P. luminescens relative to E. coli (log rank test with Bonferroni correction). The survival curve for fly larvae exposed to E. coli was not significantly different from the survival curve for the no-bacteria control (right graph); all other survival curves were significantly different from each other (P < 0.001, log rank test with Bonferroni correction). ***, P < 0.001 relative to E. coli and the no-bacteria control (log rank test with Bonferroni correction). The no-bacteria control shown in the graph was performed on LB plates; a no-bacteria control was also performed on lipid-agar plates (for comparison to P. luminescens), and results were not significantly different from those of the control on LB plates (P = 0.2728, log rank test; n = 5 to 9 trials for each condition). For all graphs, the x axis refers to time postexposure, and error bars represent standard errors of the means. In some cases, error bars are too small to be visible.