The evolution of sexual size dimorphism in the house finch. II. Population divergence in relation to local selection

Alexander V. Badyaev, Geoffrey E. Hill, Andrew M. Stoehr, Paul M. Nolan, Kevin McGraw

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

Recent colonization of ecologically distinct areas in North America by the house finch (Carpodacus mexicanus) was accompanied by strong population divergence in sexual size dimorphism. Here we examined whether this divergence was produced by population differences in local selection pressures acting on each sex. In a long-term study of recently established populations in Alabama, Michigan, and Montana, we examined three selection episodes for each sex: selection for pairing success, overwinter survival, and within-season fecundity. Populations varied in intensity of these selection episodes, the contribution of each episode to the net selection, and in the targets of selection. Direction and intensity of selection strongly differed between sexes, and different selection episodes often favored opposite changes in morphological traits. In each population, current net selection for sexual dimorphism was highly concordant with observed sexual dimorphism - in each population, selection for dimorphism was the strongest on the most dimorphic traits. Strong directional selection on sexually dimorphic traits, and similar intensities of selection in both sexes, suggest that in each of the recently established populations, both males and females are far from their local fitness optimum, and that sexual dimorphism has arisen from adaptive responses in both sexes. Population differences in patterns of selection on dimorphism, combined with both low levels of ontogenetic integration in heritable sexually dimorphic traits and sexual dimorphism in growth patterns, may account for the close correspondence between dimorphism in selection and observed dimorphism in morphology across house finch populations.

Original languageEnglish (US)
Pages (from-to)2134-2144
Number of pages11
JournalEvolution
Volume54
Issue number6
StatePublished - 2000
Externally publishedYes

Fingerprint

Finches
dimorphism
Sex Characteristics
divergence
Population
sexual dimorphism
selection intensity
Sex Preselection
sex preselection
gender
Carpodacus mexicanus
North America
Fertility
fecundity
Pressure

Keywords

  • Fecundity
  • House finch
  • Overwinter survival
  • Pairing success
  • Phenotypic selection
  • Population divergence
  • Sexual size dimorphism

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Ecology, Evolution, Behavior and Systematics
  • Agricultural and Biological Sciences (miscellaneous)
  • Genetics(clinical)
  • Ecology
  • Genetics

Cite this

The evolution of sexual size dimorphism in the house finch. II. Population divergence in relation to local selection. / Badyaev, Alexander V.; Hill, Geoffrey E.; Stoehr, Andrew M.; Nolan, Paul M.; McGraw, Kevin.

In: Evolution, Vol. 54, No. 6, 2000, p. 2134-2144.

Research output: Contribution to journalArticle

Badyaev, Alexander V. ; Hill, Geoffrey E. ; Stoehr, Andrew M. ; Nolan, Paul M. ; McGraw, Kevin. / The evolution of sexual size dimorphism in the house finch. II. Population divergence in relation to local selection. In: Evolution. 2000 ; Vol. 54, No. 6. pp. 2134-2144.
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