New Delhi, Jun 6 (PTI) New research conducted on small islands in the Bahamas has found that an evolutionary change in a lizard’s leg length can feed back into the environment, causing environmental changes in aspects such as plant growth and spider population. .
The textbook evolutionary story of peppered moths is an excellent example of how environmental change drives species evolution.
As the story goes, during the Industrial Revolution, when coal smoke darkened the bark of trees near England’s cities, black-bodied moths thrived and dominated, with targets unnoticed by predators. In contrast, the number of white-bodied people rapidly decreased.
But does a feedback loop exist in nature where the reverse process occurs? Does species evolution cause environmental change? This study, from the University of Rhode Island in the US, says that in recent years scientists have provided evidence for this.
“We really need to understand how those dynamics work so we can make predictions about how populations will survive and what kinds of environmental changes might occur,” said Jason Kolbe, a professor of biological sciences and one of the study’s senior authors.
For the study, published in the Proceedings of the National Academy of Sciences, Kolbe and his team wanted to see how the limb-long trait of the anole lizard population they’ve been studying over the past 20 years evolved in a small network. The islands of the Bahamas may affect their ecosystems.
The network is made up of 40 islands that range in size from a few dozen to hundreds of meters across — small enough for researchers to keep a close eye on the lizards that live there, and the lizards can’t easily jump off an island. Makes it possible to isolate different populations.
Brown anoles are known to adapt to surrounding vegetation due to the small diameter of brush and tree branches, and natural selection favors lizards with short legs, enabling them to move quickly when escaping predators or chasing a snack.
In contrast, lankier lizards do well in thickets of trees and plant limbs.
The idea in this study was to separate short and long lizards on their own islands, and then look for differences in how lizard populations affect the ecology of their island homes.
Using specialized lizard wangling gear, the team captured hundreds of brown anoles with particularly long or particularly short limbs. When there were separate populations of the two, they set each one free on islands previously inhabited by no lizards.
After eight months, the researchers found significant differences in the ecology of the two islands.
On islands with shorter lizards, populations of web spiders—a major prey item for brown anoles—were found to have declined by 41 percent. The researchers expected the curl-legged lizards to be well-adapted to the environment because they excel at preying on trees and shrubs and because they curl up.
Also, because short-legged lizards are better at preying on insect herbivores, plants are found to thrive.
The researchers found that buttonwood trees on islands with shorter lizards grew twice as fast as trees on islands with longer lizards.
The results, Kolbe said, could help predict environmental outcomes, particularly as human activities accelerate the pace of evolutionary and ecological change around the world. PTI KRS KRS KRS