Life history and reproductive ecology of White’s skink, Egernia whitii
David G. ChappleSchool of Botany and Zoology, Australian National University, Canberra, ACT 0200, Australia. Present address: Alan Wilson Centre for Molecular Ecology and Evolution, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand. Email: david.chapple@vuw.ac.nz
Australian Journal of Zoology 53(6) 353-360 https://doi.org/10.1071/ZO05030
Submitted: 12 June 2005 Accepted: 19 October 2005 Published: 6 January 2006
Abstract
The life history and reproductive ecology of White’s skink, Egernia whitii, was examined in a population in the Australian Capital Territory using both field and genetic studies. Colour pattern polymorphism was evident within the population, with both patterned and plain-back morphs present. Lizards typically took 3 years to reach sexual maturity, with the size at maturity being ~75 mm snout–vent length (SVL) in both sexes. There was an even overall adult sex ratio, although a slight female-bias was evident in plain-back individuals. Sexual dimorphism was evident, with males having longer and wider heads, and females having larger body size. Females generally bred annually, with mating occurring in September–October and parturition in late January–February, although the litter was produced over several days (2–10 days, mean 4 days). Litter size ranged from one to four (mean of 2.5). There was a significant relationship between maternal SVL and both litter size and relative clutch mass, but these trends were not consistent between colour morphs. An inverse relationship between litter size and offspring size (SVL and mass) was found. Comparison of the results with previous investigations of E. whitii indicates substantial geographic variation in life-history traits that is presumably associated with latitudinal variation in climatic conditions.
Acknowledgments
I thank my supervisor, Scott Keogh, for advice and encouragement at all stages of this research project. Bob Wong, Jessica Stapley, Scott Keogh, Shoko Okada, Dave Duncan and Paula Harwood provided excellent assistance in the field. I thank Michael Jennions for his statistical advice. Dave O’Connor, Adam Stow, David Milton and members of the Keogh Laboratory provided invaluable comments and discussions that greatly improved this research. Funding was provided by Australian Geographic, Australian Society of Herpetologists, ASIH Gaige Fund, Peter Rankin Trust Fund for Herpetology, Joyce W. Vickery Scientific Research Fund, Ecological Society of Australia and SSB Award for Graduate Student Research. Research was conducted with the approval of the Animal Experimentation and Ethics Committee of the Australian National University (Protocol No.: F.BTZ.36.01), under Australian Capital Territory scientific research permits LT2001105, LT200333 and K8198.
Arena, P. C. , and Wooller, R. D. (2003). The reproduction and diet of Egernia kingii (Reptilia: Scincidae) on Penguin Island, Western Australia. Australian Journal of Zoology 51, 495–504.
| Crossref | GoogleScholarGoogle Scholar |
Brana, F. (1996). Sexual dimorphism in lacertid lizards: male head increase vs female abdomen increase? Oikos 75, 511–523.
Hickman, J. L. (1960). Observations on the skink lizard Egernia whittii (Lacepede). Papers and Proceedings of the Royal Society of Tasmania 94, 111–118.
Rohr, D. H. (1997). Demographic and life-history variation in two proximate populations of a viviparous skink separated by a steep altitudinal gradient. Journal of Animal Ecology 66, 567–578.
Vitt, L. J. , and Cooper, W. E. (1985). The evolution of sexual dimorphism in the skink Eumeces laticeps: an example of sexual selection. Canadian Journal of Zoology 63, 995–1002.
