Editorial of September 26, 2024
Editorial: Keeping the Monarchs in Our Glens
It’s the end of September and the end of summer, but, happily, it’s not yet the end of the monarch butterflies, who right now are abandoning us for warmer parts south. These beautiful creatures, native to North America, exist around the globe, save for a few very cold climates. They are abundant here, during the summer, in upstate New York, bobbing across our fields, flitting about our gardens and pollinating our landscapes. They possess two pairs of orange-red wings covered with black veins and white spots that resemble stained glass and they have a wingspan of around four inches. They lay their eggs on milkweed, only milkweed, a plant that is toxic to animals and humans, and their larvae eat the leaves when they hatch. Adult monarchs live, for the most part, four to five weeks, and those in the Midwest and east of the United States undergo a magnificent and complicated migration to Mexico for the winter. They are known scientifically as Danaus plexippus, which is Greek for “sleepy transformation,” and refers to their ability to hibernate and metamorphize. Although here in New York the nine-spotted ladybird beetle, commonly known as a ladybug, is the state insect, the monarch is the state insect of Alabama, Idaho, Illinois, Minnesota, Texas, Vermont and West Virginia.
Monarchs have been steadily losing numbers—their average population in 2016 was estimated at 200 million, down 100 million from their historic numbers—but at this time they are not listed as endangered. There are two major reasons for their falling numbers: the loss of their primary food and egg-laying habitat here in the north, and the loss of their overwintering forests in Mexico.
Along with our beloved birds that have turned their energy southward and are in the midst of their migrations right now, so have the monarchs, leaving us as quickly as they appeared in the spring. But in all the world, no butterflies or insects migrate like the monarchs of North America. In fact, our monarchs exhibit the most highly evolved migration pattern of any known species of butterfly or moth—and perhaps of any known insect. While the monarchs west of the Rocky Mountains jump down to small groves along the California coast, those from east of the Rockies, including Canada, the Midwest and the Northeast, travel up to 3,000 miles, through Texas and into the Transvolcanic mountains of central Mexico, where they roost, clustered together, over 10,000 feet above sea level on steep south-facing slopes, until it is time to return north around the second week of March.
The monarchs that make this trip are different from their short-lived parents and grandparents, in that this generation is born in late summer and, due to the vagaries of temperature and humidity, is able not only to fly those many miles south, but also to overwinter and then begin their return voyage home. These guys live up to nine months. They do not make it all the way back, instead laying their eggs when they find new growths of milkweed to deposit them on along the way. Their grandchildren arrive here in the late spring, when our milkweed is up, and sire two or three more generations before that special long-living one begins its round-trip voyage to Mexico and back.
While the illegal logging of the forests of Mexico, especially of the monarchs’ favorite tree, the oyamel, have indeed contributed to their decline, research by the U.S. Fish and Wildlife Service has shown that the habitat loss of breeding grounds (e.g., milkweed) in the United States—through herbicides and urban and rural development—is the main cause of both recent and projected population declines.
If we want to save the monarchs, we must encourage the development of habitat and forage for these magnificent butterflies; we must build and support migratory way stations for them, in our gardens and in our parks and along our highways.
Leave your milkweed alone and keep our monarchs in our midst.
