by Judy Funderburk, Extension Master Gardener
Seven Monarchs Munching!
On September 7th the beautiful yellow, black and white caterpillars of the Monarch butterfly were sighted munching on the Scarlet (nonnative!) milkweed plants (Asclepias curassavica) growing by the front entrance of the Glencarlyn Library. Some of the caterpillars were babies recently hatched from the Monarch butterfly’s egg and were less than 1/2 inch long. Others had been eating and molting as they needed larger skins, approaching their full-grown size of two inches. On September 12th, we counted 25 caterpillars in varying sizes, most of them munching. The supply of milkweed plants was rapidly decreasing, but oh what a delight to share these beautiful creatures with Library patrons, including lots of children!
Monarch caterpillars eat not only the shell of the egg they emerge from, but also their own skin each time they molt (five times, each stage called an “instar”) for the vitamins it contains. They stop eating after about two weeks, and find a safe place to spin a silk button to which they attach themselves upside down. Then begins the amazing process of metamorphosis, during which the caterpillar (larval stage) becomes a chrysalis (pupa stage), within which the caterpillar changes into a butterfly. It seems miraculous that within that tiny one-inch long bright blue-green and gold-banded chrysalis the mouth parts that the caterpillar needed to chew milkweed leaves become the straw-like tongue a butterfly needs to sip nectar from flowers. And a creeping, crawling insect develops wings to fly. In less than two weeks the chrysalis cracks open to reveal a beautiful orange and black full-grown Monarch butterfly. Four to seven days after emerging from its chrysalis, the Monarch is ready to mate … and so begins the life cycle of a whole new generation.
Monarch butterflies go through four generations each year. In February, the Monarchs in Mexico come out of hibernation, mate and then fly north to lay their eggs. The eggs hatch in March and April, go through the larval and pupa stages, become butterflies, lay eggs … The second generation is born in May and June, the third in July and August. The first three generations go through the four-stage life cycle and live as butterflies for up to six weeks, but the fourth generation, born in September and October, lives on for up to six or eight months, migrating (the only butterfly to migrate, they fly 50-100 miles a day and can take up to two months to complete their journey) to the warmer climates of Mexico to hibernate and then start a new first generation each spring.
Isn’t the natural world fascinating! We’ve enjoyed learning more ourselves as people ask questions (yes, there are male and female butterflies – the males have a black spot on their hind wings!). We’re now looking for at least one chrysalis to observe. If we’re lucky, we’ll get to share with you the final stages of our Library Garden Monarch caterpillar’s life cycle before it’s time to fly away to Mexico!