The origin of Danaus plexippus, known as the monarch butterfly, is in the American Tropics, almost 2 million years ago. Its current distribution is from Canada to northeastern Argentina. Each autumn, after a 4,500 kilometer voyage, the majestic monarch butterfly arrives at its wintering grounds in Mexico to hibernate in the pine, oak, fir and mixed forests, high in the mountains.
© Hannes Strager
from Canada to northeastern Argentina
Reproductive monarchs live only 5 weeks
Each autumn they travel around 4,500 kilometers
8.9–10.2 centimetres (3½–4 in)
Tell us more...
Every autumn, millions of specimens, several generations removed from the previous year's migrants, fly south and westward from southern Canada and the United States.
A fraction of these butterflies will overwinter along the coast of California, but the vast majority will come to rest at nine or ten principal sites in the Mexican states of Michoacan and Mexico. In addition to the dangers they face from severe weather, desiccation, and predators, the overwintering monarchs must compete with humans for use of the montane fir forests which both need in order to survive.
Why do Monarchs Migrate?
Like several species of birds, bats, and whales, the Monarch butterfly of Canada and the United States migrates to places where climate is
less extreme. Winters are too cold in places where butterflies reproduce; Monarchs would not be able to withstand either heavy snowfall or the absence of plants that larval caterpillars eat. Therefore, Monarchs head south each fall, where they stand a better chance of survival as well as a chance to “return” to reproductive areas in North America and give rise to future generations of reproductive adults that can complete the annual cycle.
Why are they threatened?
The aromatic oyamel fir forest provides monarchs with the cool temperatures they need to maintain reproductive diapause, shelter from excessive cold, and an important measure of protection from predators. The balance of these factors is so critical that even moderate thinning of trees significantly raises butterfly mortality. But the fir forests also provide the villagers of Michoacan with fuel, housing materials, and income derived from selling logs to local sawmills and fibreboard factories. By the winter of 1975/76, when the butterflies were first discovered by outside observers, chain saws and logging trucks were moving into the colonies themselves, felling trees covered with monarchs.
What is WWF doing?
A major milestone in this effort has been the coordination of international experts on the biology and ecology of the monarch in 1998-2000 to improve the design of the Monarch Butterfly Biosphere Reserve. WWF also helped create the Monarch Butterfly Conservation Fund to develop economic incentives that will encourage local communities to conserve the core zones of the Reserve.
These strategies have been successful and have created good models to follow. They nevertheless need complementary efforts to strengthen and reinforce their impact.
To this end, WWF has chosen seven critical actions to strengthen monarch conservation efforts:
- Organization of the Monarch Forum
- Delivery of Economic Incentives by the Monarch Fund
- Promoting Conservation and Enforcement of Laws
- Promotion of Sustainable Tourism
- Diffusion lf Knowledge Base for Protected Areas Management
- Restoration of Forest Habitat
- Building Capacity and an Environmental Culture
© Fritz Pölking / WWF
- Do not bother the butterflies resting in the trees.
- Keep at a distance of 50 meters from the trees filled with butterflies, and do not make noise.
- Do not throw trash and avoid harming the forest plants.
- To help prevent erosion and protect the forest floor, stay on designated paths.
- If you see someone bothering the butterflies or destroying anything within the sanctuaries, report it to one of the guides, to tourist authorities, or if necessary, to the appropiate authorities of the ejido.
- If you encounter tour guides or other tourist service providers not carrying out their work responsibly, please report them to the authorities.
- As you travel through the Monarchs’ region, or if you live within it, be sure to report incidents of illegal logging or any kind of threat to species within the forests. You can contact the Federal Attorney’s Office of Environmental Protection (PROFEPA), as well as the Directorate of the Monarch Butterfly Biosphere Reserve.
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Did you know?
- The Monarch butterfly’s official name in science is Danaus plexippus, which literally means "sleepy transformation".
- Insects emerged on the planet about 300 million years ago.
- Along with beetles, bees and flies and mosquitoes, butterflies and moths are among the most numerous and diverse groups of insects on the planet.
- Adult butterflies develop sex organs within three days of emerging from their chrysalis and begin to reproduce only five days later.
- Monarch butterflies were introduced to Hawaii and Australia in the 19th century.
- The species is not in danger of disappearing, however, the Monarchs’ marvelous migratory phenomenon, has been included in IUCNs Threatened category.