This Thursday, Dr. Meghan Duffy will talk about
Infectious diseases and food webs: links between Daphnia, parasites, and the larger food web
at 12:30 in the EEB lounge (BioSciences 4338)
The seminar is hosted by the Nelson Lab
There is general interest in understanding the effects of parasites on host populations, communities, and ecosystems. My talk will be in two parts, both of which will feature the Daphnia-fungal parasite system that has been the focus of much of my research. In the first part of the talk, I will present evidence that parasite epidemics can increase host density via a hydra effect. We have found that infected Daphnia have greatly reduced feeding rates, and that, in certain environments, this can lead to higher host density during epidemics. In the second part of the talk, I will focus on how adding an invasive host species can alter host-parasite interactions. We found that the invasive host was more competent than the native host, which suggested that it should amplify disease in the native host. However, in community-scale experiments, we found that the native (lower competence) host increased disease in the invasive host. Our empirical and theoretical results suggest that these counterintuitive patterns were driven by host density, parasite degradation rates, and asymmetry in intra- and interspecific competition. Thus, host competence is not sufficient for predicting how invasive hosts will alter disease.
Dr. Duffy is a member of the EEB Department at the University of Michigan. Her lab’s research examines the causes and consequences of parasitism in natural populations, focusing on lake populations of Daphnia. The Duffy lab website can be found here.