By Shelby Stewart-Soldan
ssoldan@mihomepaper.com
In just a few months, butterflies along with other insects will appear in area fields and woodlots.
While the most people don’t count the colorful creatures of summer researchers say there may be fewer.
According to a new study, published in the journal Science, butterfly populations across the United States have dropped by 22%. The study analyzed the butterfly population trends from 2000 to 2020. Annually, that was about a 1.3% decrease across the 554 recorded species.
According to Debbie Jackson, Monarch Watch Conservation Specialist for Michigan and the northeast region, the two main reasons are habitat loss and insecticide use. The study also cited climate change as a driving factor in the southern US as the heat becomes too much to sustain the population, though that wasn’t a big factor in Michigan.
Monarch Watch is a national non-profit dedicated to education, conservation and research of the Monarch butterfly. Jackson has been raising Monarchs for over 40 years, and lives in Davisburg, and conducts Monarch outreach in the Ortonville area and beyond. While overall butterfly population is down, Monarchs are one of the species going up in population, though still below the long-term average.
“As people are expanding their range, it’s removing the range of places for wildlife,” she said. “It’s not just butterflies, it’s everything in the wild. As we have more, there’s less wild habitat for things that live in the wild. That’s quite a precarious situation.”
Loss of habitat and pesticide use can go hand in hand, as the herbicide removes plants that butterflies regularly need. Insecticide use, however, can harm the butterfly population directly.
“It’s not just monarch butterflies,” she said. “It’s a class of insecticides, neonicotinoids. That is a derivative of tobacco, you can hear the word nicotine in it. This class of insecticide is a systemic insecticide. When you apply it to the seed of the plant, it spreads throughout the plant. Any portion of that plant that is chewed on by an insect, it will kill the insect. One trillionth of a dose is enough to kill an insect.”
Herbicides also contribute as they usually target plants needed to house butterflies and caterpillars.
“In the 90s, farmers were allowed to start buying GMO corn and soy that was resistant to Round Up,” she said. “The population of the Monarch has been declining since then. Milkweed used to grow by the tons all over in the farm. When farms would plow, it would just break up the roots and spread them. But the predators of butterflies didn’t live in those fields. The Monarch didn’t have predators to eat them. But, the weeds decreased their yields. Millions of stalks of milkweed disappeared. I’m not blaming them, but this is what happened.”
While this can hurt the insect and butterfly population directly, it can also indirectly harm other animal populations as insects are part of the food chain.
“Birds need bugs to live,” said Jackson. “Even if you have a seed-eating bird, when they’re rearing their young, they depend on insects, especially caterpillars. One chickadee needs 2,000 caterpillars to be big enough to leave the nest. So a nest of three to five chicks, they will fledge in 16-18 days, and in order for them to do that, their parents will be working 6 a.m.-8 p.m. bringing mouthfuls of caterpillars to feed those young. That’s 6,000-10,000 caterpillars to get them to grow.”
The reasoning for needing caterpillars is that they are high in protein and contain no toxins, and protein is necessary for development.
“That’s how mammals develop, through the protein in milk,” she said. “All babies develop with protein. Birds do it successfully with bugs, even our seed-eating birds.”
The decrease in butterfly population is also indicative of a lack of pollinator population, she said, as pollinators are critical to wild flowers and garden plants alike.
“The butterflies are not the greatest pollinator out there, bees certainly take the crown,” she said. “Bumble bees are critical to all squashes, tomatoes. Pretty much the only vegetables that don’t need pollination are potatoes, corn and lettuce. And the only fruit available without pollination is a pineapple.”
In Michigan especially, a lack of butterflies and other pollinators could harm fruit trees and berry bushes. Northern Michigan also serves as a haven for Monarch butterflies, along the upper lower peninsula, she said, as the land has been mostly untouched and is full of plants native to Michigan.
One of the things that people can do to help butterfly populations is to allow parts of their lawn to grow wild, even a small part, and especially in rural communities that are home to more wildlife.
“If you’re not using a portion of your lawn, why not let it go back to nature and that would provide habitat for butterflies, moths, and it’ll save you a little time in mowing,” she said. “In our communities, which are rural, we do see a lot of wild spaces. But also, I see a lot of homes with one, two, three acre lawns that are all mowed with no use.”
Monarch Watch class these spaces Homegrown National Parks, which serve as monarch way-stations across the United States. They are nearing 50,000 Monarch way stations, with milkweed and nectar plants, across North America.
“People are worried about common milkweed, but there’s other milkweeds that are native to Michigan that don’t spread by root,” she said. “Marsh milkweed, it’s a very nice, thin-leaved plant that likes wet, swampy, damp ground. Or butterfly milkweed, that likes dry ground. I see butterfly milkweed most often along I-75 where the water drains away because of the steep slope. They’re both fabulous pollinators. The flowers nectar everything, bees, butterflies. Those flowers feed anything that comes to them. The leaves, however, are what the monarch caterpillars can eat.”
She also recommended using mosquito repellents instead of insecticides, which deter insects instead of killing them. They are available in many forms, including dunks to put in standing water, which can attract mosquitoes.
“It would also be beneficial to remove invasive plants that are replacing the native plants,” she said. “Most of the plants are not able to be consumed by the wildlife here. As plants and things developed over the millennia, insects evolved to eat various chemical compositions. When people bring in plants from other areas, a Japanese maple for instance, those cannot be consumed by the insects here.”
Jackson suggested willow, redbud, sugar maple, or oak trees as alternatives. She said oak trees alone host over 540 species of caterpillars and moths, and said they host more diversity of insect life than any other tree.
“We’re in Oakland County, we have oaks,” she said.
Other plants that can be good for butterfly population include carrots, Queen Anne’s lace, parsley, fennel, golden Alexander, cherry trees, walnut trees, and sumac trees.
“Any of the native nectars, cone flowers, golden rod, asters, lilacs,” she said. “For annuals, a good set of zinnias, marigolds, cosmos, those are good nectar sources. The native plants take turns feeding the population, there’s a progression.”
For more information on the Monarch conservation efforts, visit monarchwatch.org.