Living fast and dying of infection: host life history drives interspecific variation in infection and disease risk

TLDR

Parasite infections produce highly variable outcomes across host species, and ecoimmunological theory suggests a trade‑off between pathogen defenses and life‑history activities, yet this has rarely been linked to infection or disease pathology. The study tests whether a host’s pace‑of‑life predicts parasite infection and disease pathology, aiming to integrate life‑history theory with disease ecology to identify reservoir hosts and species at risk. Using a comparative experiment with 13 amphibian species exposed to a virulent trematode parasite, the authors assessed infection and pathology outcomes. Exposure to the trematode increased mortality and malformations in nine species, with fast‑developing, smaller‑metamorphosing species showing higher infection and pathology, likely due to weaker defenses and parasite adaptation to common hosts.

Abstract

Ecology Letters (2012) Abstract Parasite infections often lead to dramatically different outcomes among host species. Although an emerging body of ecoimmunological research proposes that hosts experience a fundamental trade‐off between pathogen defences and life‐history activities, this line of inquiry has rarely been extended to the most essential outcomes of host‐pathogen interactions: namely, infection and disease pathology. Using a comparative experimental approach involving 13 amphibian host species and a virulent parasite, we test the hypothesis that ‘pace‐of‐life’ predicts parasite infection and host pathology. Trematode exposure increased mortality and malformations in nine host species. After accounting for evolutionary history, species that developed quickly and metamorphosed smaller (‘fast‐species’) were particularly prone to infection and pathology. This pattern likely resulted from both weaker host defences and greater adaptation by parasites to infect common hosts. Broader integration between life history theory and disease ecology can aid in identifying both reservoir hosts and species at risk of disease‐driven declines.