Host allometry influences the evolution of parasite host-generalism: theory and meta-analysis

Josephine G. Walker, Amy Hurford, Jo Cable, Amy R. Ellison, Stephen J. Price, Clayton E. Cressler*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

11 Citations (Scopus)
274 Downloads (Pure)


Parasites vary widely in the diversity of hosts they infect: some parasite species are specialists—infecting just a single host species, while others are generalists, capable of infecting many. Understanding the factors that drive parasite host-generalism is of basic biological interest, but also directly relevant to predicting disease emergence in new host species, identifying parasites that are likely to have unidentified additional hosts, and assessing transmission risk. Here, we use mathematical models to investigate how variation in host body size and environmental temperature affect the evolution of parasite host-generalism. We predict that parasites are more likely to evolve a generalist strategy when hosts are large-bodied, when variation in host body size is large, and in cooler environments. We then explore these predictions using a newly updated database of over 20 000 fish-macroparasite associations. Within the database we see some evidence supporting these predictions, but also highlight mismatches between theory and data. By combining these two approaches, we establish a theoretical basis for interpreting empirical data on parasites’ host specificity and identify key areas for future work that will help untangle the drivers of parasite host-generalism.

Original languageEnglish
Article number20160089
Number of pages16
JournalPhilosophical Transactions B: Biological Sciences
Issue number1719
Early online date13 Mar 2017
Publication statusPublished - 5 May 2017


  • Fish parasites
  • Host range
  • Invasion analysis
  • Specialism
  • Transmission


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