If you like fireflies and butterflies

“Fall Leaves- Hanging Out With Bill” by GlacierNPS (CC PDM 1.0).

It may seem strange to think about fireflies and butterflies in autumn,

but our actions now affect how many of these creatures we will see next summer. Like many other insects, fireflies and butterflies need the insulation that fallen leaves provide to make it through our frigid winters. Firefly larvae hibernate in fallen leaves. Many species of butterflies and moths – from the Great Spangled Fritillary to swallowtails and Luna moths – overwinter in fallen leaves as eggs, caterpillars or in chrysalises and cocoons (butterflies for the former, moths for the latter). Ladybugs also enter a dormant state (known as “diapause”) often on fallen leaves as well.

We need these creatures, not only because they are beautiful to watch on warm summer days or nights, but because they perform important ecosystem services. Butterflies and moths are diurnal and nocturnal pollinators, respectively. Ladybugs and fireflies are beneficial predatory insects that eat other insects – such as aphids in the case of ladybugs – or gastropods, like snails and slugs, in the case of firefly larvae. We thus need them so that our plants and flowers can grow in a healthy and sustainable manner.

To increase the numbers of these beneficial insects that we see next summer, we can perform a simple action: leave more fallen leaves in our gardens. “Leaf mulch” is simply fallen leaves, in a layer about 1-3” deep, that provides overwintering habitat for these creatures. Leaves can be raked from lawns and spread in flower beds, keeping the leaves from smothering the base of perennials and trees.

Leaf mulch has numerous other benefits for our gardens as well. It is a free and natural “fertilizer” for our soil, one of the most nutritious gifts we can give our garden. Leaf mulch regulates soil moisture and temperature levels, allowing for fewer fluctuations, which can affect plant root growth. Leaf mulch is also a weed suppressant.

If you would like to learn more about how to conserve leaves to make leaf mulch for your garden, check out the resources below. Know that it is through these small acts of conservation and kindness now that we increase the chances of watching more fireflies and butterflies dance next summer.

Resources:

Johnson, Ken. 2019. “Using Fallen Leaves.” University of Illinois Extension. https://extension.illinois.edu/blogs/good-growing/2019-10-15-using-fallen-leaves.

Prairie Nursery. No Date. “Meaningful Maintenance: Fall Clean-Up With Positive Impact.” The Prairie Herald. https://nativeplantherald.prairienursery.com/2019/09/meaningful-maintenancefall-clean-up-with-positive-impact/.

Thuma, Jessie A. 2019. “Why you should leave the leaves (and give yourself a break from yard work!).” Tufts Pollinator Initiative. https://sites.tufts.edu/pollinators/2019/11/why-you-should-leave-the-leaves-and-give-yourself-a-break-from-yard-work/.

Xerces Society. 2020. “Nesting & Overwintering Habitat for Pollinators & Other Beneficial Insects.” https://xerces.org/sites/default/files/publications/18-014.pdf.