Advanced

Testosterone in females: Mediator of adaptive traits, constraint on sexual dimorphism, or both?

Ketterson, E D; Nolan, V and Sandell, Maria LU (2005) In American Naturalist 166(4). p.85-98
Abstract
When selection on males and females differs, the sexes may diverge in phenotype. Hormones serve as a proximate regulator of sex differences by mediating sex-biased trait expression. To integrate these perspectives, we consider how suites of traits mediated by the same hormone in both sexes might respond to selection. In male birds, plasma testosterone (T) varies seasonally and among species according to mating system. When elevated experimentally, it is known to enhance some components of fitness and to decrease others. We report that female T also varies seasonally and co-varies with male T. Female T is higher in relation to male T in sexually monomorphic species and is higher absolutely in females of species with socially monogamous... (More)
When selection on males and females differs, the sexes may diverge in phenotype. Hormones serve as a proximate regulator of sex differences by mediating sex-biased trait expression. To integrate these perspectives, we consider how suites of traits mediated by the same hormone in both sexes might respond to selection. In male birds, plasma testosterone (T) varies seasonally and among species according to mating system. When elevated experimentally, it is known to enhance some components of fitness and to decrease others. We report that female T also varies seasonally and co-varies with male T. Female T is higher in relation to male T in sexually monomorphic species and is higher absolutely in females of species with socially monogamous mating systems, which suggests adaptation. We also consider the effect of experimentally elevated T on females and whether traits are sensitive to altered T. We hypothesize that sensitive traits could become subject to selection after a natural change in T and that traits with opposing fitness consequences in males and females could constrain dimorphism. Results from birds, including the dark-eyed junco (Junco hyemalis), reveal many sensitive traits, some of which appear costly and may help to account for observed levels of sexual dimorphism. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
hormonal, sex differences, hormonal pleiotropy, correlated responses, constraint, dark-eyed junco
in
American Naturalist
volume
166
issue
4
pages
85 - 98
publisher
University of Chicago Press
external identifiers
  • wos:000232603500007
  • scopus:26644474769
ISSN
0003-0147
DOI
10.1086/444602
language
English
LU publication?
yes
id
4a3ac266-5a14-4588-9979-dc6793b57e6f (old id 218944)
date added to LUP
2007-09-28 11:41:28
date last changed
2017-10-22 03:49:19
@article{4a3ac266-5a14-4588-9979-dc6793b57e6f,
  abstract     = {When selection on males and females differs, the sexes may diverge in phenotype. Hormones serve as a proximate regulator of sex differences by mediating sex-biased trait expression. To integrate these perspectives, we consider how suites of traits mediated by the same hormone in both sexes might respond to selection. In male birds, plasma testosterone (T) varies seasonally and among species according to mating system. When elevated experimentally, it is known to enhance some components of fitness and to decrease others. We report that female T also varies seasonally and co-varies with male T. Female T is higher in relation to male T in sexually monomorphic species and is higher absolutely in females of species with socially monogamous mating systems, which suggests adaptation. We also consider the effect of experimentally elevated T on females and whether traits are sensitive to altered T. We hypothesize that sensitive traits could become subject to selection after a natural change in T and that traits with opposing fitness consequences in males and females could constrain dimorphism. Results from birds, including the dark-eyed junco (Junco hyemalis), reveal many sensitive traits, some of which appear costly and may help to account for observed levels of sexual dimorphism.},
  author       = {Ketterson, E D and Nolan, V and Sandell, Maria},
  issn         = {0003-0147},
  keyword      = {hormonal,sex differences,hormonal pleiotropy,correlated responses,constraint,dark-eyed junco},
  language     = {eng},
  number       = {4},
  pages        = {85--98},
  publisher    = {University of Chicago Press},
  series       = {American Naturalist},
  title        = {Testosterone in females: Mediator of adaptive traits, constraint on sexual dimorphism, or both?},
  url          = {http://dx.doi.org/10.1086/444602},
  volume       = {166},
  year         = {2005},
}