How do parasites affect host competition?
Infection with manipulative parasites is often associated with changes in neurotransmitters that are linked to activity, foraging, predator avoidance, and aggression. For example, F. parvipinnis infected with the manipulative Euhaplorchis californiensis trematode are known to become bolder and more active, and thus may have higher energy demands and increase foraging and other risk-taking behaviors. Manipulated killifish may additionally become more aggressive and compete more effectively for food and other resources. I am investigating how infection with E. californiensis affects killifish food competition and how parasite-associated behavioral changes killifish prey communities.
Crowding effects in parasite populations
As part of a collaborative project, we tested for resource competition in two species of manipulative trematode parasites that commonly infect California killifish, Euhaplorchis californiensis and Renicola buchanani. We did not find evidence for resource limitation with increased parasite density, and somewhat surprisingly, we observed possible evidence for positive density-dependence effects in E. californiensis. Read more about this work here: http://icb.oxfordjournals.org/content/54/2/184.full