Meeting Abstract

P3-134   -   Effects of temperature on host-disease interactions between Batrachochytrium dendrobatidis (Bd) and Xenopus laevis (African-clawed frog) Abreu Ruozzi, V*; Raffel, T; Oakland University; Oakland University abreuruozzi@oakland.edu

Amphibian populations are declining worldwide, partly due to emergence of the fungal pathogen Batrachochytrium dendrobatidis (Bd). This disease is highly temperature dependent, leading to potentially important interactions with climate change. However, mechanisms behind how climate affects temperature-dependent diseases are not fully understood, particularly in ectothermic animals where environmental temperature variation directly affects physiological performance of both the host and the pathogen. Variable-temperature environments further complicate temperature-dependent disease dynamics, due to the potential for host or pathogen thermal acclimation responses. To test for temperature and thermal acclimation effects on an ectotherm disease, and ultimately to support development of new mathematical modeling approaches, I conducted an experiment to measure effects of temperature shifts on Bd infection in the amphibian host Xenopus laevis. I acclimated animals to one of three acclimation temperatures for four weeks, then shifted them to one of five “performance” temperatures in a fully crossed experimental design. Most animals were exposed to the fungus on the same day of the temperature change (“Day 0”). However, for a subset of performance temperatures I varied the timing of Bd exposure relative to the time of the temperature shift. I compared Bd-exposed to Bd-unexposed animals to track changes in Bd infection load and host mortality in response to interactive effects of infection and temperature treatments. Results show a strong negative effect of performance temperature on Bd infection, plus a similarly strong negative effect of acclimation temperature that persisted throughout the entire 5-week performance period.