One legend states that the return of the Monarchs to Mexico at the same time as the Day of the Dead festival has prompted Mexican beliefs that the Monarchs are the returning souls and spirits of the deceased.
The monarch butterfly (Danaus plexippus) is a beautiful winged insect that measures about 90 to 100mm from wingtip to wingtip. Monarch butterflies are indigenous to Canada and the United States. They live in the Philippines, Australia, New Zealand, southern Europe, and northwest Africa, although they are not native to these places. The word monarch means king or queen. In fact, the early settlers of North America called monarch butterflies “King Billys,” after William of Orange, who became king of England in 1689. Monarch butterflies are also sometimes called milkweed butterflies. In Australia and New Zealand, people call them wanderers.
It may be hard for us in the modern world to understand how the habits and nature of a butterfly can change the way we live. But that’s exactly what happens each year in parts of Mexico where the Monarch butterfly signifies the end of one way of life and the beginning of another. It’s an essential part of indigenous folklore and rituals in large areas of Mexico; a natural time clock for the changing of the seasons. Monarch butterflies are incredibly fascinating creatures. Only recently have their life and migratory cycles been studied and recorded. Little was known of their enormous struggle for survival against such forces as nature and humans.
Monarch butterflies spend the summer months in the United States and Canada. As the weather turns colder they head south. The reason for their migration is two-fold. First of all, they can not survive the cold – temperatures below 55°F make it impossible for them to fly and when the mercury dips below 40°F they become paralyzed. Also, adult monarchs consume nectar from flowers so they need to go where they will find food. Traveling at an average speed of 12 mph (but sometimes going up to 30 mph), the monarchs cover about 80 miles a day. By the end of October, the population east of the Rocky Mountains migrates to the sanctuaries of the Mariposa Monarca Biosphere Reserve within the Trans-Mexican Volcanic Belt pine-oak forests in the Mexican states of Michoacán and México. The western population overwinters in various sites in central coastal and southern California, United States, notably in Pacific Grove and Santa Cruz.
Millions upon millions of butterflies participate in the butterfly migration, to the exact location as last year. It has been estimated that as many as 50 million may occupy a particular location, and a sole tree (same one as last year) might roost 100,000butterflies. How the monarch butterflies are able to find their way to the same wintering grounds every year remains a great mystery. One hypothesis holds that a small quantity of magnetite in the butterflies’ bodies acts as a sort of compass leading them to the magnetic iron which is found in the area of Michoacan where they spend their winters.
The monarch butterfly faces numerous threats in both its summer and wintering grounds. Habitat destruction, due to deforestation, urban sprawl, and expanding lawns, limits roosting sites and food sources. Pesticides are another serious threat – even some organic types. However, illegal logging continues in the forests that these butterflies travel to. Without the trees, no miracle can save these wonderful creatures.
The local farmers, with their focus on day-to-day survival, cut down the trees unconsciously, to clear the land in order to plant corn and raise livestock. Organizations are in place that work with the farmers, providing education and incentives to dissuade them from cutting down the trees that the Monarch butterflies call home. The hope is that a self-sustaining eco or rural tourism can be developed that allows for the local population to benefit indirectly from this natural wonder. The puzzle of the Monarch migration has inspired a program called Monarch Watch. Headquartered at the University of Kansas, it uses hundreds of volunteers across central and eastern North America to capture, tag and release Monarchs during the fall migration. If a tagged Monarch is later recaptured, the route taken by the insect can be used to better understand how they choose which way to go. Over 500 Monarchs tagged by Monarch Watch have been recaptured to date, building a database for researchers to use to understand the migration.
Many people confuse the monarch with the viceroy (Limenitis archippus), another Canadian butterfly. Although similarly marked, the viceroy has a black vein crossing the other veins on its hind wings.