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The effects of an emerging pathogen on amphibian host behaviors and interactions

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dc.contributor.advisor Blaustein, Andrew R.
dc.creator Han, Barbara A.
dc.date.accessioned 2008-10-06T18:47:21Z
dc.date.available 2008-10-06T18:47:21Z
dc.date.copyright 2008-09-26
dc.date.issued 2008-09-26
dc.identifier.uri http://hdl.handle.net/1957/9472
dc.description Graduation date: 2009 en_US
dc.description.abstract Contemporary environmental change encompasses massive biodiversity loss and increasing numbers of emerging diseases worldwide. As part of a global biodiversity crisis, amphibians are disappearing at unprecedented rates. Batrachochytrium dendrobatidis is an emerging infectious pathogen prominently associated with many declines. Chapter 1 reviews the past decade of research on this system and highlights areas where knowledge is notably lacking. Host behavior remains a crucial determinant of host-pathogen dynamics yet studies addressing the effects of Batrachochytrium on amphibian behaviors are virtually nonexistent. Remaining chapters examine behavioral responses of host species to Batrachochytrium. Chapter 2 examines how ancient behaviors that have persisted in amphibians for millions of years change with exposure to Batrachochytrium. I examined thermoregulatory behavior in tadpoles of four species (Pseudacris regilla, Rana aurora, Bufo boreas, Rana cascadae), and aggregation behavior in two species that school as tadpoles (B. boreas, R. cascadae). Results suggest that some amphibians will continue seeking optimal temperatures and continue aggregating regardless of infection risk. I discuss the importance of behavioral plasticity and evolutionary inertia in interpreting host behavioral responses to infection. Chapter 3 examines Batrachochytrium dynamics when multiple host species interact. I manipulated infection status in tadpoles of three naturally co-occurring hosts (P. regilla, B. boreas, R. cascadae) in various combinations and measured growth, survival and infection severity. There were strong interactions between species combinations and infection leading to pathogen-mediated mutualism and competition. Results also suggest that both species richness and species identity may be important factors moderating a dilution effect in this system. Coexisting, interacting hosts must also contend with predators in a community. Chapter 4 explores Batrachochytrium-induced changes in antipredator behaviors in four species (P. regilla, R. aurora, B. boreas, R. cascadae). I also examined whether antipredator behaviors increased survivorship in the presence of lethal predators in R. cascadae, R. aurora. Exposure to Batrachochytrium changed activity rate and refuge use in Bufo, but not in the other species. Nonselective predation of Batrachochytriumexposed prey by susceptible predators adds an unexplored dimension of complexity to this system. Chapter 5 summarizes the ecological implications of studies presented in this dissertation. en_US
dc.language.iso en_US en_US
dc.subject Batrachochytrium en_US
dc.subject amphibian en_US
dc.subject diversity-disease en_US
dc.subject behavioral inertia en_US
dc.subject parasite-mediated interactions en_US
dc.subject tadpole en_US
dc.subject.lcsh Batrachochytrium dendrobatidis en_US
dc.subject.lcsh Amphibians -- Pathogens en_US
dc.subject.lcsh Tadpoles -- Behavior en_US
dc.subject.lcsh Host-parasite relationships -- Environmental aspects en_US
dc.title The effects of an emerging pathogen on amphibian host behaviors and interactions en_US
dc.type Thesis en_US
dc.degree.name Doctor of Philosophy (Ph. D.) in Zoology en_US
dc.degree.level Doctoral en_US
dc.degree.discipline Science en_US
dc.degree.grantor Oregon State University en_US
dc.contributor.committeemember Kats, Lee B.
dc.contributor.committeemember Bildfell, Rob
dc.contributor.committeemember Borer, Elizabeth
dc.contributor.committeemember McEvoy, Peter
dc.contributor.committeemember Pastey, Manoj


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