Butterflies, despite their small size, possess astonishing flying capabilities. A recent international study has revealed that with the help of winds, some butterflies can fly thousands of kilometers within a few days, crossing the Atlantic Ocean, the world’s second-largest ocean.
The University of Ottawa in Canada disclosed in a press release on June 25 that an international research team discovered that the Painted Lady butterfly (Vanessa cardui) can traverse the Atlantic Ocean, flying at least 4,200 kilometers from Western Africa to French Guiana in South America.
With favorable monsoon winds aiding them, these butterflies actively flew and completed the transatlantic journey in 5 to 8 days.
Researchers described this journey as “one of the longest recorded individual insect journeys and possibly the first confirmed transatlantic migration.”
The study originated from a serendipitous discovery by Gerard Talavera, a researcher at the Botanical Institute of Barcelona in Spain. In October 2013, Talavera unexpectedly found Painted Lady butterflies on the beaches of French Guiana, a region where they do not typically appear. This discovery raised questions about the butterflies’ origins and how they reached South America.
This chance discovery led to an international research team, including Talavera and postdoctoral researcher Megan Reich from the University of Ottawa, investigating the butterflies’ migration patterns.
Initially, the team reconstructed the wind trajectories before the butterflies’ arrival in October 2013. They discovered that unusually favorable wind conditions facilitated the butterflies’ transatlantic flight from West Africa, confirming the feasibility of their journey.
Subsequently, the team sequenced the genomes of individual butterflies and compared them with global populations. They found closer genetic relationships between these butterflies and African and European populations, ruling out the possibility of their origin in North America and strengthening the likelihood of their transatlantic flight.
The researchers also analyzed the DNA of pollen grains carried by these butterflies. They concluded that the butterflies likely embarked on their transatlantic journey from regions south of the Sahara Desert in Africa, where they fed on nectar from African flowers before setting off.
By evaluating the energy expenditure of this journey, the research team assessed the feasibility of transatlantic flight. They deduced that due to favorable wind conditions, continuous oceanic flight for 5 to 8 days was achievable.
The researchers stated that the butterflies employed a strategy of alternating active flying and utilizing tailwinds for gliding, with active flying requiring significant energy consumption.
It was estimated that without winds, the butterflies could fly a maximum of 780 kilometers before depleting all their fat and energy reserves.
Regarding the study findings, one of the report’s authors, a researcher from the Institute of Evolutionary Biology at Pompeu Fabra University in Spain, Vilà, expressed his thoughts.
He stated: “We often perceive butterflies as delicate symbols of beauty, but science reveals their incredible feats. Their abilities have much yet to be explored.”
Reich said: “I believe this study effectively showcases how much we underestimate insects’ dispersal abilities. Additionally, we might completely underestimate the frequency of such dispersal events and their impact on ecosystems.”