lThe story appears in all good biology textbooks. In 1848, British entomologists observed a color change in certain moths in a forest near Manchester, United Kingdom. Instead of your usual light gray birch moths, (Biston betularia) It acquired a dark gray color, almost black.
Over the next century, the exception became the rule. In 1954, all British moths went dark. For what reason? Pollution has blackened the bark of the trees. To hide from birds, it is now better to use dark colored wings. The insect becomes a textbook case of a species’ adaptation to its environment through mutation and natural selection.
However, in the small world of evolutionary researchers we knew that the emblem had some weaknesses. The experience failed in what we call replication, or reproducibility. It is true that the phenomenon had been observed throughout England, but nothing could exclude that the populations had “contaminated” each other. “Another problem was the lack of direct evidence of the role of predation in this evolution”adds Jonathan Waters, professor of biology at the University of Otago, in New Zealand.
The academic’s team published, on October 24, in the magazine Sciencean article “who completes the manifestation”greets Patrik Nosil, CNRS research director at the Moulis center (Ariège). About another insect: the stonefly, often called the “pearl” or “stonefly.” The group has 2,000 species, spread throughout the world. But it was two of its representatives that interested Jonathan Waters.
Wood waste and leaves.
on the one hand Austropearla dark pearl with zebra legs that has the peculiarity of being toxic to those who consume it. on the other Zelandoperlajust as dark, with similar stripes, but edible. The birds don’t know the difference. So Zelandoperla is protected by Austropearl. A phenomenon that science has called “Batesian mimicry” – in homage to its discoverer, Henry Bates (1825-1892). Edifying but common, not to say banal.
Except the New Zealand researchers found that some Zelandoperla They had changed their dark dress for a light tunic. By sequencing the individuals, they discovered that this change in clothing corresponded to the mutation of a single gene. They especially noted that it had happened in areas where the forest had been subject to massive logging in recent decades, greatly reducing the population ofAustropearlwhich feeds precisely on wood waste and leaves. And they observed the same transformation in several sites completely isolated from each other.
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