Grant Sponsor: NSF; Grant number: DEB-0844523.
Water Vapor Permeability of the Rigid-Shelled Gecko Egg
Article first published online: 9 JUL 2012
© 2012 WILEY PERIODICALS, INC.
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology
Volume 317, Issue 6, pages 395–400, July 2012
How to Cite
How to cite this article: 2012. Water vapor permeability of the rigid-shelled gecko egg. J. Exp. Zool. 317A:395–400..
The author has no conflict of interest with regards to the reported research.
- Issue published online: 9 JUL 2012
- Article first published online: 9 JUL 2012
- Manuscript Accepted: 3 APR 2012
- Manuscript Received: 1 DEC 2011
- NSF. Grant Number: DEB-0844523
The vast majority of squamate reptiles (lizards and snakes) produce parchment-shelled eggs that absorb water during incubation, and thus increase in mass, volume, and surface area. In contrast, females from a single monophyletic lineage of gekkotan lizards produce rigid-shelled eggs. These eggs are functionally comparable to those of birds, that is, at oviposition, eggs contain all the water needed for development, and their mass decreases during incubation via the diffusion of water vapor through the shell. I determined patterns of water loss and shell permeability to water vapor from oviposition to hatching for the rigid-shelled eggs of the gekkonid Chrondrodactylus turneri and compared permeability of C. turneri eggs to those of birds and other squamates. Chrondrodactylus turneri eggs incubated at 28.5°C and 40% relative humidity (RH) decreased in mass by 14% over the course of a 68-day incubation period. The rate of water loss varied during incubation; egg mass decreased rapidly during the first 8 days of incubation, declined at a low constant rate during the next 35 days, and then decreased rapidly during the final 25 days of incubation. Overall permeability was 0.17 mg/day/kPa/cm2. Percent water loss of rigid-shelled gecko eggs during incubation is similar to that exhibited by birds, but water vapor permeability is about one-third that of bird eggs and several orders of magnitude lower than that of parchment-shelled squamate eggs. In general, the water economy of their eggs may be associated with the adaptive radiation of the rigid-shelled sphaerodactylid, phyllodactylid, and gekkonid geckos. J. Exp. Zool. 317A:395–400, 2012. © 2012 Wiley Periodicals, Inc.