Corresponding Author: Elizabeth Warburton
Summary by Ethan Hackmeyer
Though drylands cover over 40% of Earth’s land area and hold over a third of the world’s population, many drylands organisms, both free-living and parasitic, continue to be relatively understudied. To better understand this ecosystem and its host-parasite relationships, CEID member Elizabeth Warburton provides drylands examples on the evolution of virulence, breadth of host spectra and lifestyle strategies, in order to help stimulate future research.
Warburton reviewed studies on virulence, host spectra and lifestyle, and then constructed a general overview of drylands host-parasite relations based on these three factors. This information was then synthesized with human effects and climate change to determine future risks to, and posed by, drylands ecosystems.
The virulence of parasites is hypothesized to be lower in drylands, due to a low host density. Warburton proposes that virulence is likely low as it is more advantageous to keep a host alive for longer when there are very few hosts available to infect, though more studies need to be done to see whether this trend occurs outside of the few studied species. Parasites also likely have a wider host spectrum than their temperate counterparts, presumably owing again to low host density. In order to survive the harsh climate of some drylands regions, parasites have adapted by developing immature life cycle stages that can survive outside of a host, lifecycle synchronization with host species, and utilizing intermediate hosts before infecting the final host species.
Though Warburton creates a thorough guide to drylands ecosystems with the studies she pulls from, she notes that there are not many investigations relative to other ecosystems. In order to understand these ecosystems, more scientific examination must be performed in drylands. This research only becomes more necessary as climate change accelerates, causing desertification and an expansion of drylands ecosystems.
Warburton 2020. Untapped potential: The utility of drylands for testing eco-evolutionary relationships between hosts and parasites. International Journal for Parasitology: Parasites and Wildlife. (12) https://doi.org/10.1016/j.ijppaw.2020.04.003