Life history traits of hosts and parasites along environmental gradients

Parasitism is one of the most common consumer strategies and can impose large costs on the fitness of host individuals and populations. At the same time, environmental conditions also affect the fitness of both, host and parasite, resulting in changes in the strength and outcome of the host-parasite interaction. The relationship between changes in fitness traits (e.g. population growth, infection success) and changes in the environmental conditions are formalized in so-called reaction norms of hosts and parasites. These reaction norms are rarely assessed over the full environmental gradient. Hence, we know little about potential environmental conditions under which hosts suffer more or actually can escape from the influence of parasites. This knowledge gap hinders our understanding of disease occurrence and spread in future ecosystems under global warming and land use change.

Phytoplankton form the basis of the aquatic food web and account for up to 50% of the global primary production. Many phytoplankton species are parasitized by chytrid fungi with infection prevalence reaching as high as 90% in some populations. Phytoplankton and their chytrid parasites are good model systems for laboratory studies on the effect of environmental conditions on fitness traits as they are easy to culture and have short generation times.

We have opportunities for university / MSc students to perform a range of experimental ecological studies assessing the main and / or combined effects of temperature, nutrients and light on phytoplankton host – chytrid parasite model-systems. These experiments involve typically culturing work, microscopy for the data collection phase, statistical evaluation and presentation of the data to the working group. Please contact Alena Gsell for current openings. The duration is 6+ months.