Reprinted with permission of the National Garden Bureau:
Help Save the Beloved Monarch Butterfly
The beautiful orange and black Monarch butterfly is one of the best known threatened butterfly species in North America. According to some of the latest surveys over 90% of the population has disappeared in the last decade mostly due to loss of habitat. No one understands how this lovely insect can remember over 4 or 5 generations where to migrate. Different populations will travel from western Canada to central California or from eastern Canada, through the midwest, and southern U.S. and ultimately to central Mexico and back again.
The life cycle of the Monarch is complex and amazing. First the female lays its eggs on the underside of the leaves of a milkweed plant. After 3 to 5 days the eggs hatch and the larvae (or baby caterpillars) feed on the leaves. Over the next 9 to 15 days the caterpillars will molt 5 times increasing in mass 2000 times shedding its skin each time it molts. It then pupates and spends 9-14 days as a chrysalis. When fully developed, the adult butterflies emerge and feed on the nectar of many different flowers as they continue to fly north during the next 2 to 6 weeks. Then the process starts all over again. The butterflies mate and the females lay eggs. The Monarchs that emerge as adults at the end of the summer are different from the adults that emerge earlier in the summer. Instead of mating they spend all their time and energy feeding on nectar, flying south and catching air currents which enable them to migrate up to 2800 miles to central California or central Mexico. When they reach their destination they hibernate through the winter in trees. After several months, when the weather warms up in the spring, they begin to move northward again and females lay eggs for their first summer generation. The migrating generation of Monarchs live 7 to 9 months.
Unfortunately, sprawling urban developments and intensive farming techniques mean fewer uncultivated margins where the milkweed species can thrive and provide habitat for the Monarch during its egg and larvae/caterpillar stages. When the females cannot find suitable habitat to lay eggs, the life cycle is interrupted and the overall population decreases. While scientists have been aware for several years of the Monarch butterfly’s life threatening situation and possible extinction, promoting public, government and industry awareness of the plight of this beautiful insect is probably the only thing that can lead to saving it.
It is commonly agreed that one solution is for all aspects of our society to plant more milkweed seed to assure continuous pathways of habitat from Canada to California and Mexico where the Monarch migrates for the winter months. There are over 120 species of milkweeds (Asclepias) and several are readily available. Two species are particularly colorful, Asclepias curassavica (tropical milkweed/Bloodflower) is bright red, and A. tuberosa (butterfly milkweed) is orange. Some sources express concern when using A. curassavica as outlined here but the North American Butterfly Association says it can be used as a carefully managed garden plant as instructed below. A. tuberosa is a perennial that has been widely used in conservation and reclamation plantings. It can take 2-3 years to form a tuber before blooming. Other native species commercially available include: A. incarnata (prairie or swamp milkweed), A. speciosa (showy milkweed), and A. syriaca (common milkweed). These species have white, pale or deep pink flowers and are the most important food sources for the caterpillars to keep the butterflies healthy according to Dara Satterfield of the University of Georgia. Her studies indicate the tropical species, Asclepias curassavica may be a source for a higher rate of the butterfly parasite, Ophryocyctis elektroscirrha. Also, if A. curassavica is planted, it should be cut down in the fall to prevent the butterflies from staying too long and interrupting their normal migration schedule. Other species should be included in any tropical milkweed planting. Since showy and common milkweed are rhizomatous, they should be planted where their fast spreading habit is acceptable.
Most milkweed species are easy to start indoors from seed. The seeds are flat, brown and oval (ovate) shaped seed 1/4 to 1/2 in. long. Plant the seed indoors (4-6 weeks before intended transplanting to the garden) in a tray or pot of a light weight peat/soil/sand potting medium with good drainage and cover with 1/8 in. of the mixture. Keep well moistened in a cool sunny window or greenhouse; the seed will germinate in 10 – 14 days. Transplant seedlings into 3 to 4 in. pots until they have a well established root system. The plants can gradually be hardened off and planted outdoors in the spring or when daytime temperatures are between 60 – 70 degrees. Seeds of perennial species can also be planted directly in the ground in late summer or early spring when the soil can be tilled. Since Asclepias species do not like their roots to be disturbed, transplanting is more successful with well established plants in pots. It is a good idea to plant a mixture of other nectar producing plants with or near the milkweed to provide a food source for the emerging butterflies. Any wildflower or garden flower mixture designed to attract butterflies will serve this purpose as will annuals such as alyssum, marigold and zinnia.
The big question is how to get significant amounts of habitat re-established in appropriate parts of the country before it is too late and the Monarch becomes extinct. Everyone, including children, can help by planting more milkweed plants. Click here for an article about Children’s Butterfly Gardens.