PATERNAL INVESTMENT AFFECTS PREVALENCE OF MALARIA

Both reproduction and parasite defense can be costly, and an animal ma y face a trade-off between investing in offspring or in parasite defen se, In contrast to the findings from nonexperimental studies that the poorly reproducing individuals are often the ones with high parasite l oads, this life-history view predicts that individuals with high repro ductive investment will show high parasite prevalence, Here we provide an experimental confirmation of a positive association between parent al investment levels of male great tits Paras major and the prevalence of Plasmodium spp, a hematozoa causing malaria in various bird specie s. We manipulated brood size, measured feeding effort of both males an d females, and assessed the prevalence of the hemoparasite from blood smears. In enlarged broods the males, but not the females, showed sign ificantly higher rates of food provisioning to the chicks, and the rat e of malarial infection was found to be more than double in male, but not female, parents of enlarged broods. The findings show that there m ay be a trade-off between reproductive effort and parasite defense of the host and also suggest a mechanism for the well documented trade-of f between current reproductive effort and parental survival.