POTENTIAL MECHANISMS FOR SEX RATIO ADJUSTMENT IN MAMMALS AND BIRDS

@article{Krackow1995POTENTIALMF,
  title={POTENTIAL MECHANISMS FOR SEX RATIO ADJUSTMENT IN MAMMALS AND BIRDS},
  author={Sven Krackow},
  journal={Biological Reviews},
  year={1995},
  volume={70}
}
  • S. Krackow
  • Published 1 May 1995
  • Biology
  • Biological Reviews
Sex ratio skews in relation to a variety of environmental or parental conditions have frequently been reported among mammals and, though less commonly, among birds. However, the adaptive significance of such sex ratio variation remains unclear. This has, in part, been attributed to the absence of a low‐cost physiological mechanism for sex ratio manipulation by the parent. It is shown here that several recent findings in reproductive biology are suggestive of many potential pathways by which… 
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References

SHOWING 1-10 OF 178 REFERENCES
Sex Ratio Variation in Mammals
TLDR
Valid evidence that sex ratio trends are adaptive must be based on the overall distribution of trends or on cases in which the sex ratio can be shown to vary with the relative fitness of producing sons and daughters.
Parental hormone levels and mammalian sex ratios at birth.
  • W. James
  • Biology
    Journal of theoretical biology
  • 1989
Sex Allocation Theory for Birds and Mammals
TLDR
Since Fisher presented his explanation, many examples of biased sex ratios have been observed in nature, and the explanations put forth provided new dimensions to Fisher's central theory rather than direct exceptions.
Hormonal control of sex ratio.
  • W. James
  • Biology, Psychology
    Journal of theoretical biology
  • 1986
The question of adaptive sex ratio in outcrossed vertebrates
  • G. Williams
  • Biology
    Proceedings of the Royal Society of London. Series B. Biological Sciences
  • 1979
TLDR
Of various published theories of adaptive control of progeny sex ratio only two are plausible, a physiological theory by Trivers & Willard, and a demographic theory by Verner, which postulates a minimization of competition for mates in neighbourhoods subject to random fluctuation in sex ratio.
THE MAMMALIAN SEX‐RATIO
TLDR
It is essential to consider sex determination from a cytological and genetic viewpoint and the sex ratios and variations can be dealt with on the basis of any conclusions that have been reached.
SEX RATIO CONSTANCY IN THE RED‐WINGED BLACKBIRD
  • K. Fiala
  • Biology
    Evolution; international journal of organic evolution
  • 1981
TLDR
Trivers and Willard (1973) proposed that facultative sex ratio variation is adaptive and is compatible with Fisher's (1958) hypothesis of evolution of the mean sex ratio.
Sex-Ratio Variation in Marsupials
TLDR
The current interest in sex-determining mechanisms in marsupials suggests a profitable avenue for collaboration between geneticists, physiologists and evolutionary ecologists.
Adaptive seasonal variation in the sex ratio of kestrel broods
TLDR
The sex ratio (% males) in broods of European kestrels, Falco tinnunculus L., declined with progressive date of birth, and enhanced reproductive prospects of the broods since the probability of breeding as yearling declined with birth date for male offspring, but not for females.
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