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On the standardization of fitness and traits in comparative studies of phenotypic selection

De Lisle, Stephen P. LU and Svensson, Erik I. LU (2017) In Evolution
Abstract

Comparisons of the strength and form of phenotypic selection among groups provide a powerful approach for testing adaptive hypotheses. A central and largely unaddressed issue is how fitness and phenotypes are standardized in such studies; standardization across or within groups can qualitatively change conclusions whenever mean fitness differs between groups. We briefly reviewed recent relevant literature, and found that selection studies vary widely in their scale of standardization, but few investigators motivated their rationale for chosen standardization approaches. Here, we propose that the scale at which fitness should be relativized should reflect whether selection is likely to be hard or soft; that is, the scale at which... (More)

Comparisons of the strength and form of phenotypic selection among groups provide a powerful approach for testing adaptive hypotheses. A central and largely unaddressed issue is how fitness and phenotypes are standardized in such studies; standardization across or within groups can qualitatively change conclusions whenever mean fitness differs between groups. We briefly reviewed recent relevant literature, and found that selection studies vary widely in their scale of standardization, but few investigators motivated their rationale for chosen standardization approaches. Here, we propose that the scale at which fitness should be relativized should reflect whether selection is likely to be hard or soft; that is, the scale at which populations (or hypothetical populations in the case of a contrived experiment) are regulated. We argue that many comparative studies of selection are implicitly or explicitly focused on soft selection (i.e., frequency and density-dependent selection). In such studies, relative fitness should preferably be calculated using within-group means, although this approach is taken only occasionally. Related difficulties arise for the standardization of phenotypes. The appropriate scale at which standardization should take place depends on whether groups are considered to be fixed or random. We emphasize that the scale of standardization is a critical decision in empirical studies of selection that should always warrant explicit justification.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Experimental design, Hard selection, Phenotypic selection, Relative fitness, Soft selection
in
Evolution
publisher
Wiley-Blackwell
external identifiers
  • scopus:85029350290
  • wos:000412834700003
ISSN
0014-3820
DOI
10.1111/evo.13325
language
English
LU publication?
yes
id
50f3af34-9602-41ed-80a7-a380585e6d91
date added to LUP
2017-10-04 09:56:34
date last changed
2018-01-16 13:20:33
@article{50f3af34-9602-41ed-80a7-a380585e6d91,
  abstract     = {<p>Comparisons of the strength and form of phenotypic selection among groups provide a powerful approach for testing adaptive hypotheses. A central and largely unaddressed issue is how fitness and phenotypes are standardized in such studies; standardization across or within groups can qualitatively change conclusions whenever mean fitness differs between groups. We briefly reviewed recent relevant literature, and found that selection studies vary widely in their scale of standardization, but few investigators motivated their rationale for chosen standardization approaches. Here, we propose that the scale at which fitness should be relativized should reflect whether selection is likely to be hard or soft; that is, the scale at which populations (or hypothetical populations in the case of a contrived experiment) are regulated. We argue that many comparative studies of selection are implicitly or explicitly focused on soft selection (i.e., frequency and density-dependent selection). In such studies, relative fitness should preferably be calculated using within-group means, although this approach is taken only occasionally. Related difficulties arise for the standardization of phenotypes. The appropriate scale at which standardization should take place depends on whether groups are considered to be fixed or random. We emphasize that the scale of standardization is a critical decision in empirical studies of selection that should always warrant explicit justification.</p>},
  author       = {De Lisle, Stephen P. and Svensson, Erik I.},
  issn         = {0014-3820},
  keyword      = {Experimental design,Hard selection,Phenotypic selection,Relative fitness,Soft selection},
  language     = {eng},
  month        = {09},
  publisher    = {Wiley-Blackwell},
  series       = {Evolution},
  title        = {On the standardization of fitness and traits in comparative studies of phenotypic selection},
  url          = {http://dx.doi.org/10.1111/evo.13325},
  year         = {2017},
}