Butterflies' Journey Across the Atlantic

These are the husband's wives, or thistles, Vanessa Cardoy As its scientific name suggests, it is a widespread migratory butterfly from sub-Saharan Africa to northern Europe via the Middle East, capable of flying over the Sahara Desert and covering very long distances, up to 15,000 kilometres during its annual migrations, but with many stops and breaks to recover.

Far from borrowing their pulsating wings, the butterfly effect, researchers have long wondered how butterflies manage to fly so well and so far with wings that are so wide, so short and above all so large for their size. Swedish researchers were able to solve the mystery of butterfly flight in 2022 by demonstrating the bellows effect of their large, flexible wings that allows them to take off very quickly and fly in an erratic and unpredictable manner, which also allows them to escape predators.

Butterflies that fly 4,200 kilometers without stopping

These beautiful ladies fly on all continents, except Latin America, and the Atlantic Ocean remains their last impassable frontier, hence the surprise of the Spanish entomologist. Gerard Talavera When a flock of colourful ladies was discovered on a beach in Guyana, stranded on the sand, their wings punctured and damaged, but very much alive.

This entomologist, a formidable butterfly researcher, concluded that butterflies had just crossed the Atlantic. This new hypothesis had to be proven, but it was impossible to place a mark on the butterfly's wings. Our entomologist, who specializes in drawing women he sees and takes photographs of on all continents, decided to investigate. In 2018, he had already developed genetic tools to analyze the DNA of pollen trapped in the wings of these pollinating insects, and thus was able to trace their migratory route, and thus their path. Thanks to this innovative technique and other isotopic tools, Gerard Talavera, from the Barcelona Botanical Garden, in collaboration with an international team of entomologists, has succeeded in proving that these colorful ladies stranded in Guyana had indeed flown over the Atlantic Ocean.

In the study just published in the scientific journal nature communications, The searches showed not only that the pollen collected by the butterfly families was one of the flowers specific to West Africa – flowers that are found between August and November, which corresponds to the arrival date of these butterfly species – but that's not all. The researchers also studied the genomes of these colorful ladies stranded in Guyana and showed that their genes came from African and European butterfly lineages, but not from North America. This is yet another proof that these beauties made a non-stop transatlantic journey of 4,200 kilometers.

It reaches America instead of Africa because of strong winds.

This massive genetic, entomological and botanical research was also climatic, with particularly favorable weather conditions and winds. In fact, scientists have highlighted extremely strong winds that would have caused these beautiful ladies to deviate from their usual migration route in Africa and carry them over the Atlantic Ocean, over which they would then have flown to the northern coast of South America to wash up on this beach in Guyana.

This is the first time that trans-Atlantic migration of butterflies has been demonstrated, opening the way to a better understanding of the migration of pollinating insects in general, and painted ladybirds in particular. The latter plays a major role in the spread of flowering plants, but also fungi and even microbes or even bacteria, which are transmitted from one ocean to another across thousands of kilometers and on all continents, through the beats of the butterfly’s wings. Another type of butterfly effect remains to be explored.

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