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Painted lady butterflies travel far and wide, with impressive migration patterns spanning thousands of miles; However, they mostly travel by land so they can stop to rest.
Scientists have found evidence that a group of winged explorers flew more than 2,600 miles (about 4,200 kilometers) nonstop across the Atlantic Ocean, according to a new study published June 25 in the journal Nature Communications.
This finding is supported by entomologist and lead author of the study, Dr. It brings to an end a decade-long mystery that began when Gerard Talavera encountered about 10 painted lady butterflies, known by the scientific name Vanessa cardui, on a beach in French Guiana in October 2013. Species usually not found in South America, weathered, with holes and tears in their wings.
“They looked tired. “They weren’t even flying very much; they seemed to be jumping rather than flying,” said Talavera, a senior researcher at the Spanish National Research Council at the Botanical Institute in Barcelona. “The only explanation I can think of is that they were long-distance migrants.”
But for butterflies, even those as earthbound as the painted ladies, crossing an entire ocean was unheard of. Talavera and his colleagues had to eliminate several factors before concluding that these butterflies had accomplished something previously thought impossible.
How far can a butterfly fly
An October 2016 study co-authored by Talavera found that European painted women migrated to sub-Saharan Africa from distances as far as 2,500 miles (about 4,000 kilometers), encountering obstacles such as the Mediterranean and the Sahara Desert. Despite this, butterflies mostly stay on land where they can “stop, refuel, feed on flowers, and then get the energy to continue on their way,” Talavera said.
According to new research, it will take a female painted butterfly five to eight days to cross the Atlantic, depending on different variables.
Based on their analysis of energy constraints, the researchers concluded that the butterflies could fly a maximum of 485 miles (780 kilometers) nonstop, but Talavera said it was favorable wind conditions that allowed them to complete the long journey.
“This is actually kind of a record for an insect, especially a butterfly, to make such a long flight without the possibility of stopping,” he said, referring to the insects’ migration routes.
Talavera said there have been other cases where experts suspect butterflies and other migratory insects have traveled longer distances than usual, appearing on boats, remote islands or countries where they are not normally found.
The researchers think these butterflies participated in their annual southward migration from Europe but were lost when the wind blew them into the ocean, he added. The butterflies then probably bypassed the east-to-west trade winds near the equator and reached land in South America.
“It’s not extraordinary to be suspended in the air column at just the right height to take advantage of the trade winds,” said Dr. Floyd Shockley, collections manager of the entomology department at the Smithsonian National Museum of Natural History in Washington, D.C., who was not part of the new study. “That begs the question: Have they been doing this for a long time, and we’ve never documented it because we’re not looking for it in South America?”
The discovery of about 10 out-of-place butterflies, along with individual butterflies discovered occasionally and likely caught in storms, may be enough evidence that this was a coordinated migration event for the insect group, Shockley said.
Following a butterfly
Researchers have taken several important steps to confirm that these misplaced butterflies are indeed traveling across the ocean.
First, to rule out that the insects had not traveled overland from North America, the researchers analyzed their DNA and found that it matched that of European-African populations. Study co-author Dr. D., a postdoctoral researcher at the University of Ottawa. The team then used a technique known as isotope tracking, which looks at the composition of the butterflies’ wings for evidence of the types of plants they eat as caterpillars, Megan Reich said. Ontario. With this method, scientists concluded that the birthplace of butterflies is Western Europe, North Africa or West Africa.
But the real key to finding the route the butterflies follow was a method first described in a September 2018 study led by Talavera. In this study, it was found that pollen adhering to butterflies can give clues about their migratory journey through the plants they feed on. The pollen of the butterflies seen in October 2013 was from two plants in West Africa, Guiera senegalensis and Ziziphus spina-christi. According to the study, the tropical shrubs bloom in August and November, and this blooming season overlaps with the timeline of butterflies Talavera discovered in South America.
Additionally, the study authors noted that analysis of weather data for the 48 hours before the butterflies were discovered washed up on shore showed that it was “highly favorable for the butterflies to disperse from West Africa across the Atlantic.”
If the insects had traveled from Europe, where they likely originated, to Africa and South America, the butterflies’ journey could have been 4,350 miles (7,000 kilometers) or more.
“A lot of people think of butterflies as really fragile creatures. I think this really shows how strong and resilient they are and these incredible journeys they make — they’re really not to be underestimated,” Reich said.
The researchers added that they hope to use the same techniques to investigate the migration patterns of other butterfly species.
“This is just the first step in a long process of understanding why and how this happened,” Shockley said.
He added that if future research reveals that the butterflies’ journey has a regular migration pattern, it would be one of the longest insect migrations in the world.
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