| Determinants of embryonic stage at oviposition in the lizard Urosaurus ornatus. | |
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MedLine Citation:
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PMID: 10603328 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Relatively few squamate reptiles oviposit eggs with embryos at developmental stages greater than stage 30. To investigate potential proximate and ultimate bases of this phenomenon, we experimentally induced females of the lizard Urosaurus ornatus to retain their eggs past the normal time of oviposition (NTO). This procedure allowed us to determine whether the length of egg retention is fixed or facultative and to evaluate the effects of retention on embryos, hatchlings, and females. Females were able to retain eggs facultatively for at least 29 d past the NTO. However, retention resulted in arrested development of embryos; arrest occurred at stages 30-30.5, which is only slightly more advanced than that at the NTO (stage 29.5). Embryogenesis was reinitiated when eggs were removed from females and placed in incubation media. Hatching success of these eggs was high (87%), and incubation time was not affected by the number of days that development had been arrested. However, the snout-vent length and water content of hatchlings were negatively related to the length of retention, and they ran slower than hatchlings from control eggs obtained at the NTO. Retention of eggs past the NTO had no detectable effect on the body condition or running speeds of females. Developmental arrest and the adverse effects of retention on hatchling phenotype, if widespread among squamates, would account for the limited range of embryo stages at oviposition and act as major constraints on the evolution of viviparity. |
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Authors:
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T Mathies |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Physiological and biochemical zoology : PBZ Volume: 72 ISSN: 1522-2152 ISO Abbreviation: Physiol. Biochem. Zool. Publication Date: 1999 Nov-Dec |
Date Detail:
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Created Date: 2000-02-16 Completed Date: 2000-02-16 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 100883369 Medline TA: Physiol Biochem Zool Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 645-55 Citation Subset: IM |
Affiliation:
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Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0406, USA. tom.c.mathies@usda.gov |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Embryo, Nonmammalian / physiology Embryonic Development* Environment Female Lizards / embryology* Oviposition / physiology* Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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