September is a key time to see one the most interesting animals in our region—the monarch butterfly. The monarch makes an amazing migration down to Mexico every year—a journey that can be more than 3,000 miles! The best thing is, the monarch is relatively easy to attract to your yard.
Monarch butterflies are in the insect order Lepidoptera—an order that consists of butterflies and moths. Lepidoptera literally translates to “scale wing,” and for good reason: These creatures’ wings are covered in tiny scales, which give them their beautiful colors. All butterflies and moths go through a complete metamorphosis throughout their life cycle. This means that each stage of their life is physically very different from the last. They begin their life as an egg, the egg hatches, and out comes the caterpillar. The caterpillar has chewing mouthparts that allow it to spend its life eating, and then it pupates, forming a chrysalis (or cocoon for moths.) The butterfly will hatch out of the chrysalis and readily visit gardens to drink nectar with a straw-like proboscis and start the egg laying process all over again.
Most butterflies need a specific “host plant” on which to lay their eggs and have their hatchling caterpillars eat. Once they are adult butterflies they will feed from completely different plants. The monarch butterfly, however, could live its life exclusively on milkweed plants. The female monarch will soar over fields and gardens on the hunt for milkweed. When she lands on a likely candidate, she can “taste” that she is on the right plant with specialized chemoreceptors on her legs and abdomen. In her lifetime, a female monarch will lay about 500 eggs, but only about one in twenty of these will make it to adulthood. The egg is laid on the underside of the milkweed leaf and will hatch after three to four days. The whole lifecycle is temperature dependent, with warmer temperatures speeding up the process. After hatching, the caterpillar will eat milkweed leaves religiously for another ten to fourteen days. Once nice and plump, the caterpillar morphs into a light green chrysalis where it will stay for another ten to fourteen days. The chrysalis will begin to turn dark, and the pattern of the black and orange monarch wing will show through it once the butterfly is about to emerge. When it emerges, its wings are wet and crumpled. The monarch will pump its wings and blood from its abdomen will fill the veins in its expanding wings.
Monarch butterflies and caterpillars are toxic to most predators. They acquire their protective toxin from the milkweed plant, which has a milky sap containing cardenolides that are poisonous to most vertebrates. The bright orange coloration of the monarch is its way of telling possible predators that it is not a good meal. This type of warning coloration is known as aposematic coloration.
Arguably the most impressive feature of monarchs is the ability to migrate long distances. In the fall monarchs begin their migration southward to Mexico. This journey can take months and thousands of miles. While most monarchs only live for two to five weeks, the migratory population will live for eight or nine months. Once in Mexico, the monarchs will congregate to oyamel fir tree forests in high, mountainous elevations. They will spend the winter in these forests until March, when they begin the journey back north. These monarchs will mate and lay eggs along their journey and ultimately die off. Those eggs will continue their whole life cycle and turn into adult monarchs, called the first generation, and will continue the journey north, laying eggs all the while. This process continues for four generations. The monarchs that first make their way up to New York tend to be the third generation. It is the fourth generation that migrates back down to Mexico, meaning that those monarchs that migrate are the great-great grandchildren of the monarchs who migrated south the year before. It is a true spectacle of nature!
Monarch butterflies are relatively easy to attract to your garden. Planting nectar-producing plants like blazing star (liatris), Joe Pye weed, purple coneflower, New York ironweed, aster, and butterfly bush will attract adult monarchs. The one plant you definitely need to plant, of course, is milkweed.
In Upstate New York there are three milkweed species you are likely to find: common milkweed, swamp milkweed and butterfly weed. The common milkweed is very often found in fields, along roadsides, and parks. It has large leaves that are great for monarch caterpillars but can spread and get a bit unruly in the garden. Swamp milkweed can often be found in garden centers, especially if they have native plant sections. Its leaves are smaller and thinner but will still provide monarch caterpillars with the nutrition they need. The same goes for butterfly weed, which can also often be found in garden centers. Its bright orange, nectar producing flowers are a great treat for butterflies and it looks beautiful in the landscape.
The peak dates to see monarchs in our area are in early to mid-September. Monarchs travelling south from Canada are passing through here on their migration southward. Fields of asters and goldenrod are a great place to look. Planting for monarchs can be very rewarding, especially when you get your first visit of the season floating into the garden. These long-distance migrants are not only beautiful, but like many other pollinators, are facing population declines. So consider making your yard more monarch friendly!
Liz Magnanti is the manager of the Bird House in Pittsford.
