Evolution of hosts paying manifold costs of defence

Clayton E. Cressler, Andrea L. Graham, Troy Day

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Hosts are expected to incur several physiological costs in defending against parasites. These include constitutive energetic (or other resource) costs of a defence system, facultative resource costs of deploying defences when parasites strike, and immunopathological costs of collateral damage. Here, we investigate the evolution of host recovery rates, varying the source and magnitude of immune costs. In line with previous work, we find that hosts paying facultative resource costs evolve faster recovery rates than hosts paying constitutive costs. However, recovery rate is more sensitive to changes in facultative costs, potentially explaining why constitutive costs are hard to detect empirically. Moreover, we find that immunopathology costs which increase with recovery rate can erode the benefits of defence, promoting chronicity of infection. Immunopathology can also lead to hosts evolving low recovery rate in response to virulent parasites. Furthermore, when immunopathology reduces fecundity as recovery rate increases (e.g. as for T-cell responses to urogenital chlamydiosis), then recovery and reproductive rates do not covary as predicted in eco-immunology. These results suggest that immunopathological and resource costs have qualitatively different effects on host evolution and that embracing the complexity of immune costs may be essential for explaining variability in immune defence in nature.

Original languageEnglish (US)
Article number20150065
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1804
StatePublished - Mar 4 2015
Externally publishedYes


  • Eco-immunology
  • Host evolution
  • Immune costs
  • Immunopathology

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Environmental Science
  • General Agricultural and Biological Sciences


Dive into the research topics of 'Evolution of hosts paying manifold costs of defence'. Together they form a unique fingerprint.

Cite this