Affiliation:
1. CNRS UMR 6553; Centre d'étude biologique de Chizé, CNRS, France;
2. Centre d'étude biologique de Chizé, CNRS, France; Arizona State University, USA;
3. Arizona State University, USA;
4. CNRS UMR 6553, France
Abstract
Abstract
Examination of the selective forces behind the transition from oviparity to viviparity in vertebrates must include an understanding of the relative energy costs of the two reproductive modes. However, interspecific comparisons of reproductive mode are confounded by numerous other inherent differences among the species. Therefore, we compared oxygen consumption, as a reflection of energy costs, during reproduction in oviparous and viviparous females of the reproductively bimodal lizard Zootoca vivipara (Jaquin 1787). Female oxygen consumption progressively increased over the course of reproduction, peaking just prior to parition when it was 46% (oviparous form) and 82% (viviparous form) higher than it was at the pre-reproductive stage. Total increase in oxygen consumption (TIOC) during the pre-ovulation period was not different between the reproductive modes. Conversely post-ovulation TIOC was more than three times higher in viviparous females, reflecting dramatic increase in embryonic metabolism as well as maternal metabolic costs of pregnancy (MCP). MCP accounted for 22% of total metabolism in viviparous females, whereas it was negligible in oviparous females. Our results demonstrate that egg retention through the first third of development, as is typical of most oviparous squamates, entails minimal maternal energy demand while extending retention imposes much greater metabolic constraints. Selection for transition from oviparity to viviparity must therefore provide benefits that outweigh not only the added burden associated with prolonged embryonic retention, but also the substantial additional energy costs that are incurred.
Publisher
The Company of Biologists
Subject
Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics
Cited by
41 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献