The striking beauty of the monarch butterfly is unmistakable — but their uniqueness goes beyond the vivid orange and black wings that make them so recognizable.
These slight creatures weigh less than a dime, yet travel thousands of miles every year — 50 to 100 miles in just a day. An instinctive internal compass guides them on the same migration path as their ancestors — in spite of the fact that they have never taken the journey before. It’s nothing short of a miracle of nature.
But the butterflies that begin this majestic odyssey will never finish it. Weeks into the journey, the first generation will mate, and it’s their next generation that will continue the trek northward. The females lay their eggs on milkweed — the plant most precious to the monarch. About four days later, the caterpillars will hatch and feast on the toxic (but harmless to monarchs) leaves, storing the milkweed’s poison in their bodies.
The toxin remains in the monarch even after the caterpillar forms a chrysalis to protect itself during its two week metamorphosis, and emerges as a bright orange butterfly. The color of the monarch’s wings signals to potential predators that the monarch itself contains this poison, warning them that the butterfly tastes terrible, and ensuring the monarch’s protection.
Now adults, the butterflies continue the journey their parents started, repeating the cycle for several generations until they arrive back home.
Reference: The Future for Monarchs