Surprising study of the behavior of independent lizards shows how evolution can lead different species to acquire the same skills – sciencedaily

A surprising UNSW study of the behavior of unrelated lizards in vastly different parts of the world demonstrated how evolution can cause different species to acquire the same skills.

The study in Ecology letters documents how the Anolis lizard species in the Caribbean and the Draco lizard species in Southeast Asia have solved the challenge of communicating with each other to defend territories and attract mates.

He found that males of both species performed elaborate displays of head and push-ups, and quickly extended and retracted their often large and well-colored dewlap or throat fan, especially in habitats with lots of blown vegetation. wind or low light.

Lizards occupy the same range of rainforest and grassland habitats, and therefore face the same issues when it comes to communicating with a mate or potential enemy in visually “noisy” environments.

Remarkably, they developed the same strategy to deal with the same selection problems, said lead author Dr Terry Ord, of the Center for Evolution and Ecology Research, School of Biological, Terrestrial Sciences. and environmental issues of UNSW.

According to his research, this scenario of two independent lizards exhibiting similar behavior shows that natural selection directs evolution towards the same common set of adaptive outcomes over and over again.

“The surprise is that the lizards of both groups have developed remarkably similar displays for communication, but they also tailor the production of these displays according to the conditions prevailing at the time of posting,” says Dr. Ord.

“That is, increasing the speed or the time they spend displaying movements as the vision conditions deteriorate.

“Really, there should be countless ways these lizards could have adapted their displays to remain effective, and there are strong evolutionary predictions that would lead us to expect that as well. “

Dr Ord says this study shows that natural selection results in similarities between different species.

Formally, this is called convergent evolution – the independent origin of similar adaptations, he says.

“It seemed like these types of convergent and common adaptations are outcomes that would only really occur among closely related species to some extent,” he says.

“The reason is a little complicated and it is based on the fact that the adaptations are based on characteristics that a species already has.”

“So the more species evolved independently of each other, the less they would develop the same adaptive solutions if they were exposed to the same change in the environment.”

But what this study highlights, he says, is what many evolutionary ecologists have argued – that natural selection is an extremely powerful process that can replace the “baggage” of past history to produce the same ones. adaptations.

“So if waving the arms is the most effective solution to a change in the environment, then natural selection would ultimately lead to its evolution rather than a more subtle (less efficient) modification of an existing voice call.” he said.

“Evolutionary biologists are excited about convergent evolution because it gives us multiple examples of the same adaptation evolving over and over again in very different animals. “

“So that tells us what challenges these animals face and how they resolved them in terms of evolutionary adaptation.”

The study documents this independent evolution of common communication strategies among groups that have evolved separately from each other over hundreds of millions of years.

Dr Ord says the striking similarities in communication strategies for maintaining an effective communication system under noisy conditions have evolved in various forms in many insects, fish, frogs, birds and mammals.

“For example, increasing the volume of calls when there is a lot of acoustic background noise, or prolonging the duration of those calls or even the vibrational signals of spiders and the like,” says Dr. Ord.

“Even more extraordinary is that many other groups of animals have also developed these same coping strategies.”

Comments are closed.