Proceedings of the Royal Society of London. Series B: Biological Sciences
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Evolution of parasite virulence against qualitative or quantitative host resistance

S. Gandon

S. Gandon

Laboratoire d'Ecologie, NRS–UMR 7625 Case 237, Université Pierre et Marie Curie, Bâtiment A, 7ème Etage, 7, Quai Saint Bernard, F–75252 Paris Cedex 05, France

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Y. Michalakis

Y. Michalakis

Laboratoire d'Ecologie, NRS–UMR 7625 Case 237, Université Pierre et Marie Curie, Bâtiment A, 7ème Etage, 7, Quai Saint Bernard, F–75252 Paris Cedex 05, France

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    We analysed the effects of two different modes of host resistance on the evolution of parasite virulence. Hosts can either adopt an all–or–nothing qualitative response (i.e. resistant hosts cannot be infected) or a quantitative form of resistance (i.e. which reduces the within–host growth rate of the parasite). We show that the mode of host resistance greatly affects the evolutionary outcome. Specifically, a qualitative form of resistance reduces parasite virulence, while a quantitative form of resistance generally selects for higher virulence.