Higher temperature, blessing in disguise for lizards

The Hindu: , Saturday, January 14, 2012
Correspondent : Melbourne /PTI
Global warming may have sparked off alarm at the international level but the surge in temperature is proving a blessing in disguise for the lizards, according to a new research.

A report in the journal Biology Letter says that when lizard eggs incubated at higher temperatures, smarter lizards are hatched from them, the Sydney Morning Herald reported.

Well versed with the fact, a team of researchers from University of Sydney carried out their pursuit to figure out whether temperature also influenced a hatchling’s learning ability.

Under the study, the researchers incubated nine scincid lizard eggs in cooler temperatures (up to 23.5 degrees) and 12 in warmer temperatures (up to 29.5 degrees), the same temperatures they are exposed to in the wild.

After the hatching process, the lizards were placed in enclosures that contained two potential hiding places, one of which had the entry blocked by a see-through barrier.

Researchers did not change the position of the hiding places during the experiment, allowing the lizards to learn the location of the unblocked hide-out.

Thereafter, each hatchling was placed underneath a small plastic cover between the two hiding spaces and when the cover was removed, a researcher “scared” the lizard into action by lightly touching its tail with a paintbrush. Lizards that were able to find the open hiding place within 30 seconds were considered to have made a successful escape.

According to the report, “Overall, hot-incubated lizards achieved higher learning scores than did cold-incubated lizards, and the number of errors they made decreased more from the first to the second half of the trials...”

“Hence, factors such as maternal nest-site selection and climate change affect not only the size, shape and athletic abilities of hatchling reptiles, but also their ability to learn novel tasks.”

It was not known if poor learners went on to compensate for their mental deficit through greater sensory awareness or by basking for longer in the sun, allowing them to move at faster speeds, said Joshua Amiel, who wrote the report.

But it was likely being a faster learner could increase the lizard’s chance of survival and reproduction because it could better respond to environmental threats, he said.

However, a temperature threshold was also likely.

He did not fail to warn that if temperatures get too warm, the lizards may not develop inside the egg at all. He added, “It may be that there is a window of opportunity for lizards over the next few years, when the temperatures are ideal for them to become smarter.”

 
SOURCE : http://www.thehindu.com/sci-tech/energy-and-environment/article2801311.ece
 


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