By Jennifer Unkles Gazette Contributing Writer
It was a hot summer day and Thomas, my 3-year-old, shouted, “Mommy! There’s a Monarch Flutterby!” He saw it before I did, even though I was looking hard. We were near a clover field, which should be a good spot to catch and tag monarchs in September. I had begun to worry about the tagging program I teach and how hard it was last year to find them. Thomas brought me back to the present moment.
He’s good at that. He’s been my little helper all summer, as we’ve searched 50 to 150 milkweed plants every week. We conducted weekly monarch and milkweed surveys, measuring per-plant densities of monarch eggs and caterpillars, as part of a citizen science project with the University of Minnesota and the Monarch Larva Monitoring Project. Some weeks we found nothing; other times we found adult monarchs flying around, 40 or more eggs and many caterpillars in various stages.
As you read this, monarch butterflies from North America—including some originating here—are on their amazing 2,000-to-3,000-mile journey to Mexico and other points south. The peak migration time for our area is Sept. 5-18. At this very moment they may be flying over your head, up to 9,000 feet in the air, using the same thermal air currents as migrating birds.
But monarchs face huge challenges in their migration. They do not fly at night, in the rain, when it is below 50 degrees Fahrenheit, or when the winds are blowing northward, which is common this time of year.
Moreover, no monarch alive today has been to Mexico to show the new ones where to go. Yet they somehow complete the journey.
Most monarchs live only two to six weeks as butterflies. But every fourth generation is different: adults in this cohort migrate to Mexico, where they live six to eight months. The next three generations travel gradually back toward the north, until the fourth again migrates south. This cycle repeats over and over, in spite of habitat loss in the United States and Mexico, more frequent and stronger storms, parasites, pesticides, and climate change affecting the microclimate of their overwintering sites. That’s quite a list of challenges, with the cumulative potential of wiping out this impressive little species in my son’s lifetime.
This latest generation of monarchs will start arriving in Mexico in October and will stay there until March. Because their destination is in the mountains, it’s winter there, so there are no flowers with the nectar they need. Even so, there can be 50 million monarchs sharing one hectare (about 2½ acres) on these winter grounds. How do they live for five months without food? The cooler temperature does slow down the monarchs’ metabolism, but they are primarily living on stored fat. All those caterpillars we see in the summer are eating milkweed and storing some fat. But the big fat builder is nectar, which is what the adults feed on. Asters, clover, goldenrods and butterfly gardens are important nectar sources for them before and during their migration, since a typical monarch’s fat mass goes from 20 milligrams in August to 140 in November (and back down to 20 by April). That’s a 700 percent increase, all on a diet of sugary water from flowers.
Here in the Pioneer Valley, we can help them by planting gardens of butterflyweed, cosmos, ageratum and verbena, which are great nectar plants for these beautiful insects. And we can observe them and collect data that, along with data from hundreds of other volunteers across the continent, will aid in conserving monarchs and preserving their threatened migration.
On a personal note, I wonder what my own efforts to support monarch research are having on my son. I hope I’ve at least instilled in him a sense of awe and respect for other living things. If I’m lucky, Thomas will inherit my obsession with butterflies. Then someday you’ll hear about the legendary Tommy Verbena-Seed, planting seeds for the monarchs wherever he goes.
Jennifer Unkles is the bookkeeper at the Hitchcock Center for the Environment. She conducts annual trainings in monarch tagging. If you are interested in being a citizen scientist, check out www.mlmp.org to learn about the egg and caterpillar surveying program, www.monarchwatch.org for information on monarch tagging and butterfly gardening, and www.journeynorth.org for virtual tracking and more information about monarch migration.
Earth Matters, written by staff and associates of the Hitchcock Center for the Environment at 525 South Pleasant St., Amherst, appears every other week. For more information, call 413-256-6006, or write to us.Click here to return to full list of Earth Matters articles.