The disease pyramid: unravelling its interactions in the Daphnia magna-parasite model system

Despite the increasing consensus that parasites can have pronounced ecosystem level effects, their role in ecosystem functioning is still largely understudied. Additionally, the gut microbiota is increasingly considered as a key factor mediating performance of host individuals in continuously changing environments, whether it is challenged by parasites or not. This research project aims at obtaining insights in the role of the microbiome in eco-coevolutionary dynamics with host-parasite coevolution as the underlying evolutionary process. We aim to study how this eco-coevolutionary dynamics affect fundamental ecosystem functions, more in particular primary productivity and nutrient recycling in freshwater ecosystems. We focus on Daphnia magna, a keystone species in pelagic water systems, and multiple parasite species. We will (1) quantify the degree to which parasites may drive these ecosystem processes, (2) Examine reciprocal role of microbiome and parasite in host-parasite interactions, (3) demonstrate the potential of host-parasite coevolution to affect ecosystem functioning through eco-coevolutionary feedbacks and (4) develop predictive mathematical models to explore possible scenarios for eco-coevolutionary dynamics.