Charles Darwin was right about why insects lose the ability to fly

Most insects can fly.

Yet many species have lost this extraordinary ability, especially on islands.

On the small islands that lie halfway between Antarctica and continents like Australia, almost all the insects have.

Flies walk, moths crawl.

“Of course, Charles Darwin was aware of this wing loss habit of island insects,” says Ph.D. candidate Rachel Leihy, of the School of Biological Sciences at Monash University.

“He and the famous botanist Joseph Hooker had a substantial argument as to why this happens. Darwin’s position was deceptively simple. If you fly, you are taken to the sea. Those who remain on earth to produce the next generation are the most reluctant to fly, and ultimately evolution does the rest. Here. “

But since Hooker expressed his doubt, many other scientists have, too.

In short, they just said Darwin was wrong.

Yet almost all of these discussions have ignored the place that is the epitome of the lost theft – these “subantarctic” islands. Situated between the ‘roaring forties’ and the ‘furious fifties’, they are among the windiest places on the planet.

“If Darwin was really wrong, the wind would in no way explain why so many insects have lost their ability to fly on these islands,” Rachel said.

Using a new dataset on insects from the subantarctic and arctic islands, researchers at Monash University looked at all of the ideas proposed to account for flight loss in insects, including the idea of Darwin’s wind.

Reporting today in Proceedings of the Royal Society B, they show that Darwin was right about this “windiest place”. None of the usual ideas (such as those proposed by Hooker) explain the extent of flight loss in subantarctic insects, unlike Darwin’s idea. Although in a slightly varied form, in line with modern ideas about how loss of theft actually evolves.

Windy conditions make the flight of insects more difficult and more energy-intensive. Thus, insects stop investing in flight and its expensive underlying machines (wings, wing muscles) and redirect resources towards reproduction.

“It is remarkable that after 160 years Darwin’s ideas continue to shed light on ecology,” said Rachel, the lead author of the article.

Professor Steven Chown, also from the School of Biological Sciences, added that the Antarctic region is an extraordinary laboratory in which to solve some of the world’s most enduring mysteries and test some of its most important ideas.