Sex differences in parasite infections: Patterns and processes

摘要: Sex differences in parasite infection rates, intensities, or population patterns are common a wide range of taxa. These usually attributed to 1 2 causes: (1) ecological (sociological humans); and (2) physiological, hormonal origin. Examples the first cause include differential exposure pathogens because sex-specific behavior morphology. The second may stem from well-documented association between testosterone immune system; sexually mature male vertebrates often more susceptible carry higher burdens field. Although many researchers favor one explanation over other, requisite controlled experiments rule out confounding variables neglected. We suggest that sex disease have evolved just as morphology behavior, result selection acting differently on males females. Research has focused proximate mechanistic explanations for difference but it is equally important understand generality an evolutionary context. Because potentially gain than females by taking risks engaging competition, sexual pressure shaped appearance maximize competitive ability attractiveness. Many classic attributes such antlers deer testosterone-dependent, putting what appears be cruel bind: become vulnerable developing attractive secondary ornament, risk lowered mating success reducing it. A variety hypotheses been put forward explain why not circumvented this dilemma. system host species will influence likelihood infection, monogamous subject weaker polygynous species. Whether these generalizations apply invertebrates, which lack testosterone, remains seen.