Evolutionary ecologists study the selective forces that shape morphological, physiological, behavioral and life-history traits. Parasites are among the strongest selective agents to influence all traits related to survival and reproduction of their hosts, and are at the origin of the large diversity of animals and plants on earth (and elsewhere).

In field experiments in the forests around Bern, and on Gotland Island in Sweden, we use birds and some of their ectoparasite species as a model system to understand the ecology and evolution of host-parasite interactions and adaptive traits at the level of individuals and populations.