A winter tree that is beaten by the winds.
About 95% of the world’s insect species can fly. The question of which environmental pollution determines whether an insect species develops into wings or not has long fascinated scientists. The first known scientist to be intrigued was Charles Darwin, 22, when he visited the Portuguese island of Madeira off the coast of Morocco in January 1831.
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Madeira Island is part of a volcanic archipelago. On its dramatic rocky coast, northeast trade winds bring huge waves of the ocean with them. The temperatures at sea level in Madeira are on average in the 50s and 60s (F) in winter and are only slightly warmer in summer. It can snow in the windswept mountains. Due to its microclimate and isolation, Madeira is home to a large number of endemic species such as the Madeira long-toothed pigeon with its six-note coo and the endangered zino petrel, a seabird that lives exclusively at sea and only returns to the island to breed in the mountains. Madeira also has twenty-four species of endemic land mollusks and there are many, many beetles. Darwin was a bug lover. He picked them up on Madeira and noticed that they were wingless like no other beetle he had ever seen.
Original steel engraving by the naturalist Charles Darwin.
25 years after his trip to Madeira, Darwin mentioned the wingless beetles to his best friend Joseph Hooker, a geographic botanist and adventurer who, like Darwin, had traveled to Madeira in his younger years. For Hooker, Darwin risked a guess as to how the “apterous” (wingless) beetles had developed. He roughly suggested that Madeira is a small island with strong winds. Any flying insects would likely have been blown out into the sea and those unable to fly would have dominated the gene pool. Hooker replied that he thought Darwin’s idea was “very pretty”. At the same time, he pointed out that he had found wingless beetles in the Sahara desert, which is not near water.
Joseph Dalton Hooker
And so began a friendly argument. Darwin and Hooker never solved it, and it continued among scholars from 1855, the year the two scientists discussed it, through 2020. Researchers from Australia’s Monash University published B in the Proceedings of the Royal Society this December and finally resolved the matter. Using information about insects, microclimate and habitat stability, they showed that Darwin was right – at least when it came to identifying wind as the cause of evolutionary change.
The data used by the Monash University team was systematically collected by researchers from Antarctica and the twenty-eight islands of the Southern Ocean, which are roughly halfway between Antarctica and Australia. These islands are known for their wind speed. According to the US National Ocean Service, the winds between Australia and the South Pole drove “tall ships across the ocean at breakneck speed” during the sailing age (15th to 19th centuries).
Monash University researchers applied every believable hypothesis about apterous insect development to the insect, habitat, and microclimate information in the database. These theories included:
Dunes formed by the wind in the Sahara, Ouargla. Algeria.
· Wind, freezing temperatures or low air pressure can independently increase the energy required to fly and insects deprive insects of the energy to produce healthy sperm or eggs, find a partner or mate at all once a partner has been found. Only insects that have chosen not to fly may have the energy to reproduce well.
· Habitat fragmentation can make insects less motivated to fly.
The disappearance of predators or competitors from exceptionally uncomfortable environments can make flying unnecessary for insects.
· Wind could blow the insects off the island (Darwin’s idea).
And a few more.
When searching the databases, the researchers found that almost half (47%) of the insect species that evolved on the archipelago of islands in the Southern Ocean near Antarctica do not have wings. That is an extraordinary number, almost ten times the global incidence. When comparing variables on microclimate, island insularity, and habitat to the incidence of winglessness in insects, the team found that Darwin was likely wrong about one thing. The proportion of flightless insects on an island does not generally depend on the size of the island. Insect populations are not decimated and their species are fundamentally changed because the flying beetles are blown out into the sea. However, wind speed, habitat stability and summer land surface temperatures correlate together with 77% of the winglessness.
A traditional tall ship with reefed sails, sailing through rough seas in the southern Pacific Ocean.
The team also found that wind speed has the strongest correlation with the percentage of flightless insects. In fact, they found that the windier the island, the more flightless the insect species they identified.
In the end, the Monash University team realized that Darwin had rightly identified wind as the main driver of insect development apart from wings and flies. Still, they weren’t ready to thank him for determining exactly what the wind was that steered the evolutionary path. Where Darwin Hooker had suggested that the wind was throwing insects off the islands, Monash University researchers suggested that in environments that are very windy (like Madeira, the Sahara Desert, and the islands near the southern tip of the world), the Energy is The airfare is just way too high. Darwin had stated that all organisms are driven by a biological imperative to ensure the survival of their respective genomes in subsequent generations. If he was right, insects are much better off devoting their physiological and caloric resources to machinery and the search for reproduction than to flying in impossible environments.