A male American goldfinch. Photo by Jongsun Lee, Unsplash.

February 1, 2024

Start with One Yard: Bringing Back Beneficial Insects

Goldfinches fly away to escape the cold. Woodchucks hibernate in underground burrows, safe from the snow. But most butterflies, bees and other insects must find ways to survive the winter with the cover that is available nearby. Leaf litter, standing flower stalks, and peeling bark can all be literal life savers—if they are allowed to remain on the landscape. Intentional habitat management and modifying how we do spring yard “cleanup” has the potential to bring back beneficial insects. And it can start with one yard—yours.

Insect Apocalypse

A firefly rests on butterfly milkweek.
A firefly rests on butterfly milkweed. Fireflies are just one group of insects that are experiencing substantial population declines in the United States. Photo by Heather Griesbach.

It is estimated that there are approximately 5.5 million species of insect, representing about 80 percent of life on earth. Such large numbers can lull us into a false sense of security, but something is amiss. Scientists predict that more than 30 percent of insect species will disappear in the next 40 years—in what they are calling the insect apocalypse.

Let’s bring that statistic a little closer to home. Are you old enough to remember going out at night and quickly collecting a jar-full of fireflies or driving down a country road and having to clean the windshield because so many moths and other insects had hit the vehicle? In many places, these are no longer common experiences.

Substantial declines in insect populations will have critical and far-reaching consequences. More than 80 percent of wild plants are pollinated by insects. More than 95 percent of songbirds feed insects to their young, which depend on the protein insects provide for proper growth and development.

A savannah sparrow (Passerculus sandwichensis) prepares to feed its young, its mouth filled with a grasshopper and spider.
A savannah sparrow (Passerculus sandwichensis) prepares to feed its young, its mouth filled with a grasshopper and spider. Photo by Pete Nuij, Unsplash.

And insects serve other vital ecological roles in addition to pollination and serving as a food source for other wildlife. Some insects are decomposers, converting dead plants and animals, as well as animal waste, into nutrients that can be taken up again into the food web. Other beneficial insects help control populations of insects that people consider pests. And roughly 35 percent of the world’s food crops depend on pollinators to reproduce.

The declines in insect diversity, abundance and biomass are caused by a combination of habitat loss, use of pesticides and herbicides, light pollution and climate change. While thinking about the problem at a global scale can quickly become overwhelming, taking steps in your own yard to improve habitat is easy.

Supporting Biodiversity

A diversity of plants helps to ensure a diversity of insects. Most insects live and die within a relatively small area. If the plants they and their offspring need for food and cover are not available nearby, those populations die out. Notice what insects you currently have in your yard and then add native plants that support those species. A yard planted with a diverse group of native plants will support more insects than a yard that is covered in turfgrass. Keeping or adding native trees and shrubs is also important, as they serve as food for an amazing number of caterpillars and other larvae.

It’s Not Messy…It’s Nature

Fallen deciduous leaves in the fall.
Fallen leaves that are allowed to remain on the landscape provide critical winter cover for a diverse number of insects and spiders that birds and other wildlife depend upon for food. Photo by Courtney Smith, Unsplash.

Recent research by Max Ferlauto, PhD candidate at the University of Maryland Entomology Department, and others is helping to guide the steps people can take to preserve hibernating insects in our yards. We’ve known for a while that it is important to leave the leaves. His research underscores the need to leave leaf litter on the landscape. Ferlauto found that bagging up leaf litter reduced moth emergence from winter hibernation by almost half. He also reported that shredding and mulching leaves destroyed the insects clinging to the leaves and was almost as bad for biodiversity as bagging up the leaves. The study noted that it is important to keep intact leaves on the ground because the leaves serve as a “blanket for insects.” Some insects literally wrap themselves up in the leaf litter, but others burrow into the soil. Ferlauto found that areas where the leaves were removed had reduced capacity for temperature buffering.

Habitat Helpers

If you are interested in supporting local insect populations, there are simple steps to take. Here’s a list of 10 things you can do to improve insect habitat where you live.

  1. Plant native plants
    Where possible, purchase local plants that are grown from seed and that are not cultivars.
  2. Reduce the size of your lawn
    Once established, native plants require less water and reduce the need to use herbicides.
  3. Remove invasive plants
    Invasive plants outcompete the native plants that insects depend upon.
  4. Dim the lights
    Artificial light increases the risk of predation for moths and other nocturnal species and reduces reproductive capacity of others, such as fireflies.
  5. Oppose mosquito spraying
    Spraying for insects reduces populations of beneficial species as well. And mosquitoes serve as a main food source for bats, many of which are also experiencing population declines.
  6. Don’t use bug zappers or fly ribbons
    These products indiscriminately kill both beneficial and pest insects. And fly ribbons can be sticky enough to trap and kill small birds.
  7. Leave the leaves and hollow plant stems
    Leaves and hollow plant stems provide critical overwintering habitat for insects such as bees and wasps. While it may be tempting to “clean up” the yard once it begins to warm up outside, wait until temperatures are consistently above 50 degrees. The longer you can wait, the more time you give insects time to emerge.
  8. Add rock or brush piles
    Rock or brush piles provide critical winter habitat for adult butterflies such as the mourning cloak as well as for many species of beetles, millipedes, snails and spiders.
  9. Participate in No Mow May
    No Mow May is an effort to encourage people to delay mowing long enough for flowers in their lawns bloom to support pollinators in the spring.
  10. Tell your friends and neighbors
    One yard that is insect-friendly helps. Neighborhoods of insect-friendly yards are even better. To stem the decline of insect populations we’ll need to work together across cities, counties and states to provide quality habitat.

If your neighbors make a fuss…tell them “It’s not messy…it’s Nature.” And then start a conversation about the importance of supporting wildlife in our own yards.

Laura Kammin is a Natural Resources Specialist with the National Great Rivers Research and Education Center. She formerly held positions at Illinois-Indiana Sea Grant, University of Illinois Extension, Prairie Rivers Network and the Illinois Natural History Survey. She received her master’s degree in wildlife ecology from the University of Illinois, Urbana-Champaign.

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