Publication Date:
2015-09-22
Description:
The Trivers-Willard theory proposes that the sex ratio of offspring should vary with maternal condition when it has sex-specific influences on offspring fitness. In particular, mothers in good condition in polygynous and dimorphic species are predicted to produce an excess of sons, whereas mothers in poor condition should do the opposite. Despite the elegance of the theory, support for it has been limited. Here we extend and generalize the Trivers-Willard theory to explain the disparity between predictions and observations of offspring sex ratio. In polygynous species, males typically have higher mortality rates, different age-specific reproductive schedules and more risk-prone life history tactics than females; however, these differences are not currently incorporated into the Trivers-Willard theory. Using two-sex models parameterized with data from free-living mammal populations with contrasting levels of sex differences in demography, we demonstrate how sex differences in life history traits over the entire lifespan can lead to a wide range of sex allocation tactics, and show that correlations between maternal condition and offspring sex ratio alone are insufficient to conclude that mothers adaptively adjust offspring sex ratio.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schindler, Susanne -- Gaillard, Jean-Michel -- Gruning, Andre -- Neuhaus, Peter -- Traill, Lochran W -- Tuljapurkar, Shripad -- Coulson, Tim -- England -- Nature. 2015 Oct 8;526(7572):249-52. doi: 10.1038/nature14968. Epub 2015 Sep 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Oxford, Department of Zoology, Oxford OX1 3PS, UK. ; Laboratoire de Biometrie et Biologie Evolutive (UMR 5558), Universite Claude Bernard Lyon 1, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France. ; Department of Computer Science, University of Surrey, Guildford GU2 7XH, UK. ; Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada. ; School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Wits 2050, South Africa. ; Department of Biology, Stanford University, Stanford, California 94305, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26390152" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
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Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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