A new study of the Reading University reveals that the Painted Lady butterfly is making the longest known migration of any insect. The researchers have found that if the weather conditions are suitable, the butterflies can migrate thousands of kilometers from the Sahara to Europe.
The experts report that the butterflies travel 12,000 to 14,000 kilometers and make this incredible journey in greater numbers when wetter conditions give certain desert plants a boost.
“We know that the number of Painted Lady butterflies in Europe fluctuates greatly, sometimes by a hundredfold from one year to the next,” said study co-author Professor Tom Oliver. “However, the conditions that caused this were unknown and the suggestion that the butterflies could cross the Sahara and oceans to reach Europe has not been proven.”
“This research shows that this unlikely journey is possible and that certain climatic conditions that lead to train season have a huge impact on the number it creates. It shows how the wildlife we see in the UK can cross national borders and protecting these species requires strong international cooperation. “
The results could help experts predict the movements of other insects, such as the locusts that are currently plaguing East Africa or mosquitoes that transmit malaria.
“We are excited to see the beautiful Painted Lady butterflies in our gardens in Europe, but climate change will also shift invasive species that are plant pests or spread diseases,” said Professor Oliver. “The food shortage in East Africa is a reminder that the effects of climate change can be much more dramatic than a few degrees of warming initially suggest.”
The Painted Lady breeds in winter and migrates in spring. The study focused on long-term monitoring data from thousands of trained volunteer recorders. The experts also analyzed climate and atmospheric data in sub-Saharan Africa and Europe.
The researchers found that there are three main factors influencing the number of painted lady butterflies migrating to Europe, including increased vegetation in the African savannah in winter, increased vegetation in North Africa in spring, and favorable tail winds.
The plants that support the Painted Lady caterpillars thrive in wetter winter conditions in sub-Saharan Africa, causing population numbers to skyrocket. If spring conditions are ideal in North Africa, the population will continue to grow.
The study also showed that favorable tail winds regularly occur between Africa and Western Europe, which give the butterflies a certain amount of help. To use this, the butterflies had to fly up to three kilometers above sea level, the experts found.
Based on observations of similar butterfly species, the experts concluded that after metamorphosis, painted lady butterflies have enough body fat to be able to fly non-stop for 40 hours. They gain extra energy by feeding on nectar whenever possible.
The study is published in the journal Proceedings of the National Academy of Sciences.
By Chrissy Küster, Earth.com Employed author
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