Quantification and decomposition of environment-selection relationships

Darren C Hunter, Josephine M Pemberton, Jill G Pilkington, Michael B Morrissey

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

In nature, selection varies across time in most environments, but we lack an understanding of how specific ecological changes drive this variation. Ecological factors can alter phenotypic selection coefficients through changes in trait distributions or individual mean fitness, even when the trait-absolute fitness relationship remains constant. We apply and extend a regression-based approach in a population of Soay sheep (Ovis aries) and suggest metrics of environment-selection relationships that can be compared across studies. We then introduce a novel method that constructs an environmentally structured fitness function. This allows calculation of full (as in existing approaches) and partial (acting separately through the absolute fitness function slope, mean fitness, and phenotype distribution) sensitivities of selection to an ecological variable. Both approaches show positive overall effects of density on viability selection of lamb mass. However, the second approach demonstrates that this relationship is largely driven by effects of density on mean fitness, rather than on the trait-fitness relationship slope. If such mechanisms of environmental dependence of selection are common, this could have important implications regarding the frequency of fluctuating selection, and how previous selection inferences relate to longer term evolutionary dynamics.

Original languageEnglish
Pages (from-to)851-866
Number of pages16
JournalEvolution: International Journal of Organic Evolution
Issue number4
Early online date8 Mar 2018
Publication statusPublished - 16 Apr 2018

Keywords / Materials (for Non-textual outputs)

  • Environmental heterogeneity
  • natural selection
  • phenotypic selection coefficients
  • quantitative genetics


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