Fig. 1

Sexual dimorphism in survival to infection of an outbred population. a Survival upon infection with the Gram-negative bacteria P. rettgeri. Females were more susceptible than males (Cox-ph: df = 1, χ² = 23.26, P < 0.0001). b Survival upon infection with the Gram-positive bacteria Enterococcus faecalis. Females were more susceptible than males (Cox-ph: df = 1, χ² = 5.96, P = 0.015). c Survival upon infection with the Gram-negative bacteria P. alcalifaciens. Females were more susceptible than males (Cox-ph: df = 1, χ² = 42.49, P < 0.0001). d Survival upon infection with the Gram-positive bacteria Staphylococcus aureus. Males were more susceptible than females (Cox-ph: df = 1, χ² = 7.37, P = 0.006). e Survival upon injection of PBS (sterile solution used for bacterial suspension). Females were slightly more susceptible than males (Cox-ph: df = 1, χ² = 5.66, P = 0.02). f Survival of the genotype Canton S upon infection by the Gram-negative bacteria P. rettgeri. Females were more susceptible than males (Cox-ph: Sex: df = 1, χ² = 49.42, P < 0.0001). g Survival of the genotype Oregon R upon infection by the Gram-negative bacteria P. rettgeri. Females were more susceptible than males (Cox-ph: Sex: df = 1, χ² = 16.09, P < 0.0001). h Survival of the genotype w ¹¹¹⁸ upon infection by the Gram-negative bacteria P. rettgeri. Females were more susceptible than males (Cox-ph: Sex: df = 1, χ² = 4.36, P = 0.036). i Dose response in survival of Canton S to P. rettgeri infection. Females were more susceptible than males (Cox-ph: Sex: df = 1, χ² = 96.97, P < 0.0001) and the dose had an effect on survival (Dose: df = 1, χ² = 8.09, P = 0.004). This effect was dependent on the host sex as a 100-fold difference in starting dose was not enough to remove the dimorphism in survival (Dose*Sex: df = 1, χ² = 5.64, P = 0.017). j Survival of mated males and females and virgin females upon infection with the Gram-negative bacteria P. rettgeri. Mated males are more resistant than mated females (Cox-ph adjusted for multiple tests: Sex: df = 1, z = 4.6, P < 0.001) and virgin females (Cox-ph adjusted for multiple tests: Sex: df = 1, z = 2.34, P = 0.045). Mated and virgin females were marginally non-significant in difference in survival (Cox-ph adjusted for multiple tests: Sex: df = 1, z = 2.31, P = 0.054)