The evolutionary ecology of faking sick

Natural selection often produces traits that enable organisms to detect and avoid infected conspecific or environments deemed to be of high risk for parasite acquisition. We propose that such traits could foster the evolution of dishonest signals of infection. We describe herein instances where dishonest signals of infection could be favored by natural selection and the various costs and benefits likely to be associated with them. We further review the available evidence suggesting that such traits could evolve and the ecological contexts which might foster or impede their evolution. Finally, we provide a model verifying that a stable frequency of dishonest signalers of infection can be maintained in populations, at least in principle, and that the stable frequency of dishonest signalers increases with the prevalence of the infection. We conclude that dishonest signals of infection could evolve and be maintained in a variety of systems and warrant further scrutiny.