| Different optimal offspring sizes for sons versus daughters may favor the evolution of temperature-dependent sex determination in viviparous lizards. | |
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MedLine Citation:
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PMID: 16405171 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Temperature-dependent sex determination (TSD) has evolved independently in at least two lineages of viviparous Australian scincid lizards, but its adaptive significance remains unclear. We studied a montane lizard species (Eulamprus heatwolei) with TSD. Our data suggest that mothers can modify the body sizes of their offspring by selecting specific thermal regimes during pregnancy (mothers with higher and more stable temperatures produced smaller offspring), but cannot influence sons versus daughters differentially in this way. A field mark-recapture study shows that optimal offspring size differs between the sexes: larger body size at birth enhanced the survival of sons but reduced the survival of daughters. Thus, a pregnant female can optimize the fitness of either her sons or her daughters (via yolk allocation and thermoregulation), but cannot simultaneously optimize both. One evolutionary solution to reduce this fitness cost is to modify the sex-determining mechanism so that a single litter consists entirely of either sons or daughters; TSD provides such a mechanism. Previous work has implicated a sex difference in optimal offspring size as a selective force for TSD in turtles. Hence, opposing fitness determinants of sons and daughters may have favored evolutionary transitions from genetic sex determination to TSD in both oviparous turtles and viviparous lizards. |
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Authors:
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Tracy Langkilde; Richard Shine |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Evolution; international journal of organic evolution Volume: 59 ISSN: 0014-3820 ISO Abbreviation: Evolution Publication Date: 2005 Oct |
Date Detail:
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Created Date: 2006-01-12 Completed Date: 2006-02-09 Revised Date: 2008-06-04 |
Medline Journal Info:
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Nlm Unique ID: 0373224 Medline TA: Evolution Country: United States |
Other Details:
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Languages: eng Pagination: 2275-80 Citation Subset: IM |
Affiliation:
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School of Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia. langkild@bio.usyd.edu.au |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Body Size* Body Temperature Evolution Female Lizards / genetics, physiology* Male Sex Determination (Genetics)* Sex Ratio* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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