Scaling effects of temperature on parasitism from individuals to host–parasite systems

Abstract

Parasitism - the interaction between a parasite and its host - is expected to change in a warmer future, but the direction and magnitude of this change is uncertain. One challenge is understanding whether warming effects will be similar on individual hosts (e.g., parasite burden) compared to on population-level parasitism (e.g., prevalence, R0). Examining thirteen empirical systems, we found a strong positive relationship between the thermal optima of individual- and population-level parasitism. We also found that parasitism thermal optima were close to host performance thermal optima in mosquito - parasite systems but not in non-mosquito - parasite systems. A simple mechanistic model showed how population-level parasitism thermal optima can be similar to individual-level parasitism thermal optima even under conditions where parasite transmission has a considerably higher thermal optimum. These results provide a key step towards finding general rules for how warming temperatures should affect parasitism in individuals, populations, and ecosystems.

Global Patterns of the Fungal Pathogen Batrachochytrium dendrobatidis Support Conservation Urgency

“…Regional patterns warrant additional study at smaller spatial scales, and relative to additional interactions among environmental covariates. At smaller scales, relationships between temperature and the pathogen biology, host biology, and their interplay could be further explored (85). Spatially downscaled approaches could have ramifications for the direction of regionally specific conservation actions to forestall disease threat, such as site-specific efforts to manage microclimate conditions (86).…”