Project title: Investigating predation by freshwater zooplankton on the zoospores of Batrachochytrium dendrobatidis, a fungal pathogen of amphibians
Summary: Predation upon parasites is an important and ubiquitous trophic interaction which can significantly affect transmission dynamics. Understanding disease dynamics when the parasite is consumed by predators requires knowledge of the wider ecology of both host and parasite. My PhD is investigating how freshwater zooplankton communities consume the spores of Batrachochytrium dendrobatidis (Bd), a fungal pathogen responsible for severe amphibian population declines worldwide. Despite a global distribution, huge heterogeneity in infection prevalence exists at smaller spatial scales. Much of this variability is explained by abiotic factors, but the biotic community plays a significant role too. In nature, predatory zooplankton densities correlate with reduced risk of infection and, under experimental conditions, reduce the abundance of Bd’s infectious, free-swimming zoospores, with subsequent decreases in infection in hosts. I am exploring this relationship in-depth, quantifying each link in the host-parasite-predator interaction network. Using controlled experimental mesocosms combined with field data I am combining disease dynamics with trophic ecology, linking fundamental ecological theory with real world variation and applicability. Understanding how biotic communities affect Bd transmission will hopefully improve predictions of disease outcome, guide novel mitigation strategies and aid in amphibian conservation.