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Fig. 2 | BMC Biology

Fig. 2

From: The Toll pathway underlies host sexual dimorphism in resistance to both Gram-negative and Gram-positive bacteria in mated Drosophila

Fig. 2

Sexual dimorphism in resistance to P. rettgeri. a P. rettgeri load in Canton S (CS) flies over 10 days of infection. Overall, females carried more bacteria than males. We did not detect differences in bacterial load in early time points (Wilcoxon test: 8 h: W = 151.5, P = 0.1102; 16 h: W = 151, P = 0.1148; 24 h: W = 60, P = 0.52). However, after 48 h post-injection, when the mortality plateaued and the infection can be considered chronically persistent, females carried a higher burden than males (Wilcoxon test: 2 days: W = 99.5, P = 0.01; 3 days: W = 171.5, P = 0.0007; 5 days: W = 202.5, P = 0.0002; 7 days: W = 188, P = 0.0003; 10 days: W = 152, P = 0.0005). b P. rettgeri load upon injection in flies from an outbred population. Females carried more bacteria than males during the chronic phase of infection of P. rettgeri in the three independent experiments looking at three different time points of the infection (Wilcoxon test: 3 days: W = 262.5, P = 0.01; 10 days: W = 1162, P < 0.0001; 30 days: W = 2148, P < 0.0001). c P. rettgeri load 10 days post-injection in flies from wildtype genotypes. For the three genotypes, females carried more bacteria than males during the chronic phase of infection of P. rettgeri (Wilcoxon test: CS: W = 350, P < 0.0001; w1118: W = 692.5, P = 0.0001; Oregon R (OrR): W = 513, P = 0.0001). d Bacterial load upon death (BLUD; +30 min maximum) in both sexes of CS and OrR flies. We did not detect a significant sexual dimorphism in P. rettgeri load at death (Welsh t test: CS: df = 255.28, t = –1.77, P = 0.08; OrR: df = 235.58, t = 0.6, P = 0.54). Both sexes succumbed at the same bacterial load. Black lines in b, c, and d represent the means. The violin plots represent the distribution of the data, the quartiles and the median. Wilcoxon tests comparing medians: *P < 0.05, ****P < 0.0001, and ns: P > 0.05. e Within-host dynamic of P. rettgeri in males and female CS flies between 8 and 16 h post-injection. In both experiment replicates (i and ii), males have controlled the bacterial proliferation before females (estimated t c, or time of control, is represented by the vertical red lines and the confidence interval around the estimate is shaded in gray). Each dot represents the bacterial load in a single fly, the solid line represents the standard Baranyi bacterial population growth fitted to the white dots (see Methods and [50]). The intensity of red in the dots represents the inferred probability that the host controlled the infection (see Methods and [50])

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