Meeting Abstract

125-3  Thursday, Jan. 7 14:00  Effect of temperature on chytridiomycosis in larval amphibians BRADLEY, P. W.*; BRAWNER, M.D.; RAFFEL, T.R.; ROHR, J.R.; OLSON, D.H.; BLAUSTEIN, A.R.; Oregon State University, Corvallis, OR; Oregon State University, Corvallis, OR; Oakland University, Rochester, MI; University of South Florida, Tampa, FL; USDA Forest Service, Pacific Northwest Research Station; Oregon State University, Corvallis, OR paul.bradley@science.oregonstate.edu http://chytridiomycos.is

Climate models predict changes in the frequency and magnitude temperature fluctuations, with potential implications for infectious disease. Prior studies of Batrachochytrium dendrobatidis (Bd) infection in adult amphibians support the hypothesis that temperature variability increases disease susceptibility in ectotherms. Using 40 independently controlled temperature chambers, we experimentally tested whether a temperature shift (from warm to cold or from cold to warm) would alter larval susceptibility to Bd infection in red legged frogs (Rana aurora) and western toads (Anaxyrus boreas). Both host species responded to temperature similarly. Both harbored elevated Bd infection intensities under the constant cold (15° C) temperature in comparison to the constant warm (20° C) temperature. Additionally, both species experienced an increase in Bd abundance when shifted to 20° C compared to a constant 20° C, but they experienced a decrease in Bd when shifted to 15° C compared to a constant 15° C, resulting in a strong shift-by-exposure temperature interaction. These results support the “lag effect” hypothesis, which predicts that shifts from cold to warm and from warm to cold might increase and decrease amphibian susceptibility to pathogens, respectively.