A trend toward more females and fewer males in a type of Australian reptile may actually benefit the species in the short-term, a discovery that's contrary to previous research, a new study says.
As temperatures rise due to global warming, so does the proportion of female spotted skinks, reptiles found only on Australia's island state of Tasmania.
In recent years researchers have shown concern that climate change will push the reptiles into extinction by causing their young to be born of one gender, thus limiting future reproduction. Temperature-driven gender also occurs in other reptiles, such as crocodiles and turtles.
(Related: "Warming May Drive Gender-Bending Reptiles Extinct, Scientists Say" [November 10, 2006].)
But an increase in female spotted skinks could lead to larger populations of the reptiles, experts say.
The research is described online this week in the Journal of Animal Ecology.
Female Explosion
Erik Wapstra at the University of Tasmania in Hobart wondered to what extent temperature-driven gender occurred in nature, since most of the studies have been done in the laboratory.
From 2000 to 2007, Wapstra and colleagues observed a wild population of spotted skinks, recording the gender of their offspring and monitoring the air temperature.
Temperatures that averaged around 62.6 degrees Fahrenheit (17 degrees Celsius) when the creatures were pregnant led to mostly male offspring, while in warmer years the offspring were more likely to be female.
No one knows why the phenomenon occurs, although a longstanding theory holds that the reptiles' genes have been selected to produce offspring that will best survive their environment.
For instance, if warm temperatures are better for male survival, than males will tend to be born in warm conditions, and vice versa.
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