Unpredictable daily and monthly temperature fluctuations decrease frogs’ resistance to the pathogenic chytrid fungus, which is thought to be responsible for dramatic declines in amphibian population around the world. The findings, published online this week in Nature Climate Change, warn that if similar acclimation responses influence other host-parasite systems, then ignoring the effect of temperature variability might lead to poor predictions of climate change effects on disease.
Few studies have considered the effects of changes in climatic variability on disease incidence in animals. Thomas Raffell and co-workers address this using laboratory experiments and field data from Latin America. They find that frog susceptibility to the chytrid fungus Batrachochytrium dendrobatidis is influenced by temperature variation and its degree of predictability, with more unpredictable changes limiting opportunities for adaptive behaviour.
They note that the response of the fungus on frogs was opposite to the pattern of growth in laboratory cultures, demonstrating the importance of host-parasite interaction in determining disease dynamics.