Natural selection on a measure of parasite resistance varies across ages and environmental conditions in a wild mammal.
J Evol Biol
; 24(8): 1664-76, 2011 Aug.
Article
em En
| MEDLINE
| ID: mdl-21658142
Parasites detrimentally affect host fitness, leading to expectations of positive selection on host parasite resistance. However, as immunity is costly, host fitness may be maximized at low, but nonzero, parasite infection intensities. These hypotheses are rarely tested on natural variation in free-living populations. We investigated selection on a measure of host parasite resistance in a naturally regulated Soay sheep population using a longitudinal data set and found negative correlations between parasite infection intensity and annual fitness in lambs, male yearlings and adult females. However, having accounted for confounding effects of body weight, the effect was only significant in lambs. Associations between fitness and parasite resistance were environment-dependent, being strong during low-mortality winters, but negligible during harsher high-mortality winters. There was no evidence for stabilizing selection. Our findings reveal processes that may shape variation in parasite resistance in natural populations and illustrate the importance of accounting for correlated traits in selection analysis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Seleção Genética
/
Doenças dos Ovinos
/
Tricostrongilose
Limite:
Animals
Idioma:
En
Revista:
J Evol Biol
Assunto da revista:
BIOLOGIA
Ano de publicação:
2011
Tipo de documento:
Article