The Monarch butterfly (Danaus plexippus) is one of the best known and most striking insects in the world. Although they can be found on five continents, the phenomenon of their migration of more than 2,600 miles, from the cold mountains of the United States and Canada to the temperate forests of central Mexico, only occurs in North America.
It is believed that early European immigrants named them on behalf of William III, Prince of Orange and King of England.
This impressive migration was known by ancient Mexicans, who related butterflies to the souls of their deceased, but no one knew where they came from until Canadian researchers, Nora and Fred Urquhart, with the help of researchers and thousands of volunteers, managed to trace their route and found their hibernation sites in 1975, in the mountains between Michoacán and the State of Mexico.
The Methuselah Generation
Once the route was clarified, the next mystery to be solved was how a little insect that weighs half a gram is able to travel half a continent and still return. The researchers discovered that “normal” Monarch butterflies live for just a month, but as autumn approaches, a generation very different from their parents and grandparents is born, known as “Methuselah” and capable of living between seven and eight months.
How does a small insect born in the far northern mountains manage to fly with precision to Monarch sanctuaries it has never been to before? Scientists theorize that they achieve this by following the orientation of the sun, according to the website SoyMonarca.
"Generación matusalen"— CONABIO (@Conabio) October 21, 2020
Año tras año, a principios del otoño, en agosto y septiembre, cuando los días empiezan a hacerse más cortos y las temperaturas disminuyen, sucede un fenómeno extraordinario.
Conoce más en https://t.co/QQbUUAt6lp#MariposaMonarca pic.twitter.com/okni6Im6L1
Years later, scientists discovered that this migration is the most numerous and involves about 90% of the Monarchs of North America, but it is not the only one.
Groups of Monarch butterflies from the Carolinas and move down to South Florida, where they meet with local resident populations. Later, a part of them continues their journey through Cuba, Jamaica, Puerto Rico, the Dominican Republic and other Caribbean islands until they reach the Yucatan peninsula, in Mexico.
Monarch Butterflies in Mexico.
Butterflies and humans travel to the Caribbean in winter for the same reasons: to flee from the intense cold. The butterflies return in the spring, laying their eggs the long way north, where they also shed enormous amounts of pollen, helping to keep the ecosystems they travel diverse and healthy. There is also data about migration of Monarchs along the California coast.
Less Monarchs every day
The presence of the monarch butterfly decreased 26% in hibernation sanctuaries in Mexican forests compared to the previous year, according to the World Wildlife Fund (WWF).
Among the main threats to the monarch is the intensive use of agrochemicals in North America, the destruction of its habitats, the climate crisis and the destruction of its overwintering forests, due to the continuous pressure to replace them with avocado fields.
This pressure has generated conflicts that could be related to the murder of Homero Gómez, a leader of defenders of the Monarch forests, among activists in the region who have also lost their lives.
Efforts to conserve them
In Mexico, indigenous and peasant communities joined forces with authorities, researchers and organizations to create a fund that offers productive alternatives to the inhabitants so that they are forced to cut down their forests or convert them into farmlands.
In the United States, a group of legislators presented a bill that would allocate $ 125 million in emergency funds, spread over five years, to save the western population of monarch butterflies from extinction.
The measure would impact the butterfly populations of Arizona, California, Idaho, Nevada, Oregon, Utah and Washington, which travel each winter to the California coast. According to data, last winter
In 2020 only 1,914 monarchs were recorded wintering off the California coast, the lowest number ever recorded.
Overall, monarch populations in the United States have plummeted more than 80% in the past two decades. Without emergency aid, the western monarch population will almost certainly disappear in 50 years. In fact, their annual migration has already collapsed.
If in the future you want to experience this wonderful natural spectacle, you can travel to Central Mexico where the Monarch Butterfly Sanctuaries are located. Although this year many activities were impeded by the pandemic, communities are hopeful of receiving thousands of visitors next season.