Meeting Abstract
Parasites are known to reduce survival, but the extent to which this cost varies between sexes is generally unknown. Males are often assumed to have greater parasite loads and suffer greater costs from parasitism, however, females also invest substantially in reproduction and may face similar costs. To test for a sex bias in the extent to which parasitism reduces survival we conducted a meta-analysis using studies that measured the survival costs of parasitism on males and females simultaneously, both vertebrate (n=18) and invertebrate (n=21) species were included. We also characterized each species with respect to mating system (Promiscuous, Polygynous, Monogamous) and sexual size dimorphism (male-biased, monomorphic, female-biased) to test whether these proxies for sexual and sex-specific selection predict variation in the extent to which males and females suffer survival costs of parasitism. Our results confirm that parasites are costly, with parasitized individuals facing a 3.2-fold increase in the risk of mortality, however, this increase did not differ by sex. Moreover, neither of the predictive variables we tested had a significant effect on the difference in costs between males and females. However, we found that promiscuous species faced higher survival costs of parasitism than monogamous and polygynous species. In addition, species with female-biased SSD faced greater survival costs then those with no bias or with a male-biased SSD. Males and females in promiscuous systems may each have steeper Bateman gradients than in monogamous and polygynous systems and thus may both benefit from increased investment in reproduction at the expense of survival.
