Sick of Eating: eco-evo-immuno dynamics of predators and their trophically acquired parasites

When predators consume prey, they risk becoming infected with their preys parasites, which can then establish the predator as a secondary host. For example, stickleback in northern temperate lakes consume benthic or limnetic prey, which are intermediate hosts for distinct species of parasites (e.g. Eustrongylides nematodes in benthic oligocheates and Schistocephalus solidus copepods in limnetic copepods). These worms then establish the stickleback as a secondary host and can cause behavioral changes linked to increased predation by birds. In this study, we use a quantitative genetics framework to consider the simultaneous eco-evolutionary dynamics of predator ecomorphology and predator immunity when alternative prey may confer different parasite exposures. When evolutionary tradeoffs are sufficiently weak, predator ecomorphology and immunity are correclated among populations, potentially generating a negative correlation between parasite intake and infection.