Meeting Abstract

P1.207  Wednesday, Jan. 4  Climate variability reduces frog resistance to parasitic infection RAFFEL, TR; HERBIG, E*; KOBASA, C; VENESKY, M; MCMAHON, TA; ROHR, JR; Dickinson College; Dickinson College; University of South Florida; University of South Florida; University of South Florida; University of South Florida tomraffel@gmail.com

Climate change is expected to change the distribution and abundance of important diseases of humans and wildlife. Most studies of climate and disease have focused on changes in mean temperature and precipitation, but have ignored potentially important effects of climate variability on host-parasite interactions. In a previous study, we showed that frogs were more susceptible to the pathogenic fungus Batrachochytrium dendrobatidis (Bd) following an unpredictable shift in temperature. In this study, we tested whether this effect is generalizable to two additional amphibian parasites: the bacterium Aeromonas hydrophila and the nematode parasite Rhabdias. Using 40 replicate incubators, we acclimated Cuban treefrogs (Osteopilus septentrionalis) to 15°C or 25°C for four weeks. Half were then switched to the other temperature, at which point, one frog in each incubator was exposed to Bd, Aeromonas, or Rhabdias. A fourth frog was subjected to control inoculations. The frogs were monitored for an additional 6 weeks in their incubators. Bd infection was measured at 2 and 4 weeks post-exposure using quantitative PCR; Rhabdias infection levels were assessed at 1, 2, 3, and 6 weeks by examination of frog feces. Rhabdias-infected frogs were killed and dissected at the end of the experiment for quantification of adult Rhabdias worms in their lungs. We found that all three parasites grew faster in frogs that were subjected to an unexpected temperature shift, supporting our hypothesis. Given that many frog populations are thought to be in decline due to disease, this result has potential implications for the effects of climate change on amphibian declines and extinctions worldwide.