Erik E. Osnas


Assistant Scientist (former)


Current Contact




Research Interests
I am generally interested in the ecology and evolution of host-parasite associations.  Currently, I am working on statistical models to estimate prevalence and transmission (“force-of-infection”) of Chronic Wasting Disease (CWD) in white-tailed deer of southern Wisconsin.  I am then using these models to assess management actions taken by the Wisconsin Department of Natural Resources to control CWD. 
Ph. D. – Biology, Indiana University, 2004.  Thesis title:  Evolutionary Ecology of Host Defense in a Snail-Trematode Interaction. 
Master of Science – Zoology, University of Western Ontario, 1998.  Thesis title:  Temporal and Spatial Structure of Waterfowl Communities.
Bachelor of Science – Wildlife and Fisheries Biology, University of California, Davis, 1995.
Osnas, EE and CM lively. 2006. Host ploidy, parasitism, and immune defense in a coevolutionary snail-trematode system. Journal of Evolutionary Biology 19: 42-48.
Osnas, EE and CM Lively.  2005.  Immune response to sympatric and allopatric parasites in a snail-trematode interaction.  Frontiers in Zoology 2:  8.
Janssen, MA and EE Osnas.  2005.  Adaptive capacity of social-ecological systems: lessons from immune systems.  Ecohealth 2(2):  93-101.
Lively, CM, Dybahl MF, Jokela J, Osnas EE, and Delph LF.  2004.  Host sex and local adaptation by parasites in a snail-trematode system.  American Naturalist 164:  S6-S18.
Osnas EE and Lively CM.  2004.  Parasite dose, prevalence of infection and local adaptation in a host-parasite system.  Parasitology 128: 223-228.
Osnas EE.  2003.  The role of competition and local habitat conditions for determining occupancy patterns in grebes.  Waterbirds 26(2):  209-216. 
Osnas EE and Ankney CD.  2003.  Null models of North American prairie duck communities:  local habitat conditions and temporal scale influence community patterns.  Evol. Ecol. Res.5:  913-932.
Manuscripts in revision, in preparation, or submitted:
Osnas, EE and CM lively.  Larval trematode communities produced by New Zealand waterfowl:  implication for host-parasite coevolution.  (unsubmitted manuscript).
Osnas, E.E., G. Wasserberg, J.A. Blangchong, and M.D. Samuel.  2005.  Spatial and demographic patterns of chronic wasting disease  prevalence in the south-central Wisconsin disease eradication zone.  Second International Chronic Wasting Disease Symposium, Madison, Wisconsin, July 2005.  (Invited)
Host defense in a coevolutionary snail-trematode system.  The Evolution Conference, 2004. 

Effects of parasite density on parasite growth rate and host immune induction.  Department of Biology and Center for the Integrative Study of  Animal Behavior, Indiana University, 2002

Null models of SW Manitoba dabbling duck communities: morphology, habitat, and time. Second North American Duck Symposium, 2000.
Disjunct wetland use of horned and pied-billed grebes.  North American Ornithological Conference, 1998.
Other Interests:
Hunting, shooting, fly-fishing, fly-tying, cooking