Do sexual ornaments demonstrate heightened condition-dependent expression as predicted by the handicap hypothesis?
The handicap hypothesis of sexual selection predicts that sexual ornaments have evolved heightened condition-dependent expression. The prediction has only recently been subject to experimental investigation. Many of the experiments are of limited value as they: (i) fail to compare condition dependence in sexual ornaments with suitable non-sexual trait controls; (ii) do not adequately account for body size variation; and (iii) typically consider no stress and extreme stress manipulations rather than a range of stresses similar to those experienced in nature. There is also a dearth of experimental studies investigating the genetic basis of condition dependence. Despite the common claim that sexual ornaments are condition-dependent, the unexpected conclusion from our literature review is that there is little support from well-designed experiments.
Cotton
Samuel
S
The Galton Laboratory, Department of Biology, University College London, 4 Stephenson Way, London NW1 2HE, UK.
Fowler
Kevin
K
Pomiankowski
Andrew
A
D000818:Animals; D005075:Biological Evolution; D001824:Body Constitution / Q000502:physiology*; D005260:Female; D008297:Male; D012641:Selection, Genetic; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000502:physiology*