Rebecca Manzi Butterflies of the Vanessa cardui species have flown non-stop for over 4,200 kilometers across the Atlantic Ocean using the currents
@Jean-Pol GRANDMONT/Wikimedia
Butterflies of the Vanessa cardui species have achieved an extraordinary feat: a nonstop flight of over 2,600 miles across the Atlantic Ocean, from West Africa to South America, in less than eight days, aided by favorable wind currents.
This exceptional migration was documented in a study published in Nature Communications, conducted by an international team led by the Botanical Institute of Barcelona. The discovery occurred in October 2013, when Gerard Talavera, an entomologist at the Botanical Institute of Barcelona, found some Vanessa cardui butterflies on a beach in French Guiana.
The butterflies, typically migrating between Europe and sub-Saharan Africa, were not native to South America, raising questions about their journey. To understand the origin of these butterflies, researchers adopted a multidisciplinary approach.
They analyzed wind trajectories, discovering a corridor that could have facilitated their journey from Africa to South America. Additionally, by studying the genetic diversity of the butterflies, they determined that the specimens found in South America were genetically linked to populations in Europe and Africa, ruling out a North American origin.
Much credit goes to Saharan air currents
The analysis of pollens found on the butterflies’ bodies revealed two plant species that grow only in tropical Africa, confirming that the butterflies had visited flowers in that region. Moreover, the examination of hydrogen and strontium isotopes on the butterflies’ wings indicated that their larval life took place in Western Europe, in countries like France, Ireland, the United Kingdom, and Portugal.
This suggests that the butterflies might have undertaken a journey of over 4,300 miles, crossing three continents. Experts also highlighted the impact of Saharan air currents, which transport dust and sand from the Sahara Desert to South America, fertilizing the Amazon.
These currents could have facilitated the butterflies’ flight, allowing them to alternate between active flight and gliding, conserving energy. Without wind support, the butterflies could only have covered about 485 miles before exhausting their energy reserves.
Implications of this study
This study demonstrates how butterflies, often considered fragile, can accomplish incredible feats. However, climate change could further encourage these long-distance dispersal events, with significant implications for biodiversity and global ecosystems.
