Monarch waystations are places that provide resources necessary for monarchs to produce successive generations and sustain their migration. Without milkweeds throughout their spring and summer breeding areas in North America, monarchs would not be able to produce the successive generations that culminate in the migration each fall.
Similarly, without nectar from flowers, these fall migratory monarch butterflies would be unable to make their long journey to overwintering grounds in Mexico. The need for host plants for larvae and energy sources for adults applies to all monarch and butterfly populations around the world.
What You Can Do
The first line of action is to offset the loss of milkweeds and nectar sources by creating, conserving and protecting milkweed/monarch habitats. Gardeners can help monarchs by creating "monarch waystations" (monarch habitats) in home gardens, at schools, businesses, parks, zoos, nature centers, along roadsides and on other unused plots of land. Without a major effort to restore milkweeds to as many locations as possible, the monarch population could decline to extremely low levels.
Monarch waystations contribute to monarch conservation, an effort that will help assure the preservation of the species and the continuation of the spectacular monarch migration phenomenon.
Monarch larvae appear to feed exclusively on milkweeds in the genus Asclepias and several other genera of vine milkweeds in North America.
Milkweeds are perennial plants, which means an individual plant lives for more than one year, growing each spring from root stock and seeds rather than seeds alone. In the Midwest, milkweeds were historically common and widespread on prairies, but habitat destruction has reduced their range and numbers.
Photo: Asclepias tuberosa, more commonly known as Butterfly Weed.
Milkweeds belong to the family Asclepiadaceae, derived from Asklepios, the Greek god of medicine and healing. Though most members of the genus Asclepias are tropical, there are approximately 110 species in North America known for their milky sap or latex contained in the leaves. Most species are toxic to vertebrate herbivores if ingested due to the cardenolide alkaloids contained in the leaves and stems.
When monarch larvae ingest milkweed, they also ingest the plants' toxins, called cardiac glycosides. They sequester these compounds in their wings and exoskeletons, making the larvae and adults toxic to many potential predators. Vertebrate predators may avoid monarchs because they learn that the larvae and adults taste bad and/or make them vomit.
There is considerable variation in the amount of toxins in different species of plants. Some northern species of milkweed contain almost no toxins while others seem to contain so much of the toxins that they are lethal even to monarch caterpillars.