Evolutionary implications of host-pathogen specificity: the fitness consequences of host life history traits

Citation
Jw. Kirchner et Ba. Roy, Evolutionary implications of host-pathogen specificity: the fitness consequences of host life history traits, EVOL ECOL, 14(8), 2000, pp. 665-692
Citations number
87
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
EVOLUTIONARY ECOLOGY
ISSN journal
0269-7653 → ACNP
Volume
14
Issue
8
Year of publication
2000
Pages
665 - 692
Database
ISI
SICI code
0269-7653(2000)14:8<665:EIOHST>2.0.ZU;2-A
Abstract
Pathogens and parasites can be strong agents of selection, and often exhibi t some degree of genetic specificity for individual host strains. Here we s how that this host-pathogen specificity can affect the evolution of host li fe history traits. All else equal, evolution should select for genes that i ncrease individuals' reproduction rates or lifespans (and thus total reprod uction per individual). Using a simple host-pathogen model, we show that wh en the genetic specificity of pathogen infection is low, host strains with higher reproduction rates or longer lifespans drive slower-reproducing or s horter-lived host strains to extinction, as one would expect. However, when pathogens exhibit specificity for host strains with different life history traits, the evolutionary advantages of these traits can be greatly diminis hed by pathogen-mediated selection. Given sufficient host-pathogen specific ity, pathogen-mediated selection can maintain polymorphism in host traits t hat are correlated with pathogen resistance traits, despite large intrinsic fitness differences among host strains. These results have two important i mplications. First, selection on host life history traits will be weaker th an expected, whenever host fitness is significantly affected by genotype-sp ecific pathogen attack. Second, where polymorphism in host traits is mainta ined by pathogen-mediated selection, preserving the genetic diversity of ho st species may require preserving their pathogens as well.