Temperature variability and amphibian disease

Background/Question/Methods

Disease outbreaks among wildlife have surged in recent decades alongside climate change. However, it remains unclear how climate change alters disease dynamics across different geographic regions. For example, multiple studies have documented seemingly conflicting patterns in how environmental temperature affects amphibian susceptibility to the fungal pathogen Batrachochytrium dendrobatidis (Bd) with studies determining that both heat pulses and cool weather drive epidemics. We resolve these discrepancies using a lab experiment to determine how individual- and population-level host thermoregulatory behavior influence Bd growth and a meta-analysis to determine how interactions between a population’s adapted climate and weather influence Bd-induced mortality.

Results/Conclusions

Our experiment revealed that for populations that preferred warmer temperatures, the preferred temperatures of individuals were negatively correlated with Bd growth on hosts, while the opposite correlation was true for species preferring cooler temperatures. Further, our meta-analysis showed that host mortality was also driven by thermal mismatches: hosts native to warmer environments experienced greater Bd-induced mortality at relatively cool experimental temperatures and vice versa. Our results suggest that individual-level behavior and interactions between adapted climate and weather might shape the outcomes of Bd infections for individuals and populations.