Communal nesting in reptiles and amphibians
A gravid female Delicate Skink
( Lampropholis delicata) searches for a
nest site in Lane Cove River National Park, Sydney.
Photo by Sean Doody. Animals that group together can perform feats not possible by individuals alone. A major type of grouping behaviour is communal breeding, whereby mothers lay eggs in shared nest sites. Although communal nesting is widespread in animals, decades of research have failed to expose a common explanation for this behaviour.
Most of what we know about communal breeding stems from studies of birds. However, birds are socially complex and exhibit extreme parental care, inflating the number of possible explanations and obscuring any commonality. Reptiles offer ideal systems for studying the evolution of communal nesting because they generally lack post-ovipositional parental care, and they are socially simple. Thus, byproduct explanations would be fewer in reptiles. For example, because mating and nesting are temporally dissociated, mate choice could not explain communal nesting in reptiles. Other explanations raised for communal nesting in birds would not apply to brief-nesting reptiles, such as group protection from predators, kleptoparasitism, and following multiple neighbors to food sources.
We recently reviewed communal nesting in reptiles and amphibians, and proposed hypotheses for why communal nesting would evolve in those groups. We are now testing these ideas in a population of communally-nesting skinks we recently discovered.
What animals are we studying, where, and with whom?
A gravid Delicate Skink adds her eggs to a
communal nest site, a sandstone crevice. Photo
by Sean Doody. Our current focus is with the delicate skink (Lampropholis delicata), a small leaf-ltter lizard endemic to Australia and introduced in New Zealand, Hawaii, and Lord Howe Island. What these skinks lack in their charisma they make up for in their habits, and communal nests have been reported to contain >300 eggs (mothers lay 2-5 eggs per clutch).
We are studying the behaviour, ecology, ecophysiology, genetics, and embryonic development in this species at Lane Cove National Park, Sydney. The population is unusual for skinks in offering large numbers of conspicuous nests.
We collaborate with the laboratories of Steve Freedberg, St. Olaf College, USA, and Mike Thompson, University of Sydney.
Articles stemming from our research and funding sources
Articles
- Cheetham, E., Doody, J. S., Stewart, B., and Harlow, P. 2010. Embryonic mortality as a
cost of communal nesting in the delicate skink. Journal of Zoology, London (In press).
- Doody, J. S., S. Freedberg, and J. Scott Keogh. 2009. Communal nesting in reptiles and
amphibians: evolutionary patterns and hypotheses. Quarterly Review of Biology 84:229-252.
- Reebs, S. 2009. Herp hatcheries: Nest sharing is surprisingly common among reptile
moms. Natural History Magazine, Samplings, November 2009.
(http://www.sciencedaily.com/releases/2009/09/090903093149.htm)
- Doody, J. S. 2006. Communal nesting in the Red-throated Skink, Bassiana platynota. Herpetofauna 36:23-24.
Funding
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