In all the world, no butterflies migrate like the monarchs of North America. They travel up to three-thousand miles twice a year: south in the fall and north in the spring. To avoid the long, cold northern winters, monarchs west of the Rocky Mountains winter along the California coast. Those east of the Rockies fly south to the mountain forests of Mexico. Unlike migrating birds and whales, however, individual monarchs only make the round-trip once. It is their great-grandchildren that return south the following fall.
The monarch butterfly is sometimes called the “milkweed butterfly” because its larvae are laid on and then upon hatching, eat the milkweed plant. In fact, milkweed is the only thing the larvae can eat.
Many people like to attract monarchs by making a butterfly garden. If you live in the right area of the country and would like to attract monarchs to your garden, you can try planting milkweed. Milkweed seed can be purchased online if your local nursery or home improvement store does not carry it. Many people enjoy raising butterfly gardens simply for pleasure, and others do it for educational or preservation reasons.
Due to the presence of cardenolide aglycones in the monarch’s body that occurs as a result of feeding on milkweed, the monarch butterfly is foul-tasting and poisonous to most of its predators. In a phenomenon known as aposematism, monarch butterflies advertise their dangerous nature with bright colors and areas of high contrast on their skin or wings. Many other members of the animal kingdom also advertise their poisonous potential with bright colors. There are, however, also copy-cat insects and animals that have adapted similar appearances as a means of protection, but are not poisonous.
Monarchs are unique in that they migrate south to a given over-wintering site every year. Just like birds, when the monarch senses a change in the weather, they migrate to a warmer climate. Monarch butterflies that go south do not succeed in returning to where they were born. Most monarch butterflies will die before their migration is through. However, as they lay their eggs along the path of their migration, their children, grandchildren and even great grandchildren simply carry on where their parents left off.
What’s even more amazing is that these new young monarch butterflies are able to continue in the same direction as their parent’s migrating process without any help from their elders.
The monarch butterfly has a puzzling innate ability to navigate across continents to find their winter home. Every year on the flight to and from warmer climates, the monarch’s short-lived offspring, with only four or five weeks to live, continue making the northbound or southbound trek over several generations.
Recent deforestation of the monarch’s over-wintering grounds in Mexico has led to a drastic reduction in the butterfly’s population (as the butterflies, for whatever reason, always return to the same location every season). When their migration destination of milkweed plants is destroyed, they have no place to lay their eggs and therefore threatening future butterfly generations. Efforts to classify the monarch butterfly as a protected species and to restore its habitat are under way, and experts now are more optimistic about the future of the monarch butterfly.
For more about monarch butterflies, with links to recommended sites, visit Monarch Butterflies at “Surfing the Net with Kids.”