You may have heard the phrase “leave the leaves” before. It was first coined by the National Wildlife Federation, then popularized by the Xerces Society. After that, many other groups followed suit. Before we dive into what that phrase means, let’s talk a bit about the decline of insects and other arthropods, more casually referred to as “bugs.”
The Decline
[CREDIT: Dr. Max Ferlauto, Maggie Lin; University of Maryland]
It’s not news that bugs have had a rough time in recent years. Numerous articles have shown concerning statistics when it comes to biodiversity loss, and the trend has yet to be reversed.
There are several possible causes that can be cited as an influence, including habitat loss, fragmentation, uptick of disease, misuse of pesticides, seasonal shifts, and more. Especially in our home state of Florida, we are dealing with more development, leaving less and less habitat for bugs.
In 2024, it’s estimated that an average of 900 people moved to the Sunshine State each day. While this may help boost our local economy, it also puts a strain on our natural areas. In addition, many homeowners are concerned with the appearance of their landscape, which might lead to excess use of pesticides and fertilizer. It also often means disposing of the “unsightly,” which might include leaf litter. Removing leaf litter negatively impacts the bugs that live inside it and might slow down the decomposition process as a result.
Importance of Leaf Litter
Traditionally, the “Leave the Leaves” campaign takes place in the fall, with October being formally designated as “National Leave the Leaves Month.” In Florida, however, while many plants drop their leaves in winter, some may continue into the rest of the year. One infamous example is the live oak (Quercus virginiana), which tends to drop its leaves when it begins to grow new ones in the spring. This leaf litter provides nesting materials and habitat for several bugs, including butterflies, moths, bees, and spiders. For some, such as the charismatic luna moth, it may be a critical part of their life cycle. To help support these bugs, consider leaving the leaves year-round, as they have more than a seasonal reliance on leaf litter in Florida.
Meet the Leaf Litter Locals
There are many local bugs that rely on leaf litter for at least part of their life cycle. Below are a handful of interesting species that can be found in our area.
Two-striped walkingstick (Anisomorpha buprestoides)
[CREDIT: UF/IFAS, Lyle Buss]
Named for its distinct pattern, the two-striped walkingstick is Florida’s only known walkingstick species. Some of its nicknames include the devil’s riding horse, prairie alligator, stick bug, witch’s horse, devil’s darning needle, scorpion, and musk mare. The latter name refers to its defensive musk, released as a painful spray when potential predators get too close.
A female two-striped walkingstick will lay her eggs directly on the ground near where she feeds. Adult walkingsticks have been observed to feed on a variety of leaves, including oak, rosemary, and lyonia. While not much is known about their life history, it is said that they are most active in the fall when they lay their eggs.
If you ever encounter one of these two-striped beauties, take care to observe it from a safe distance, as its defensive spray can reach over a foot long.
American bumblebee (Bombus pensylvanicus)
[CREDIT: UF/IFAS, James Castner]
[CREDIT: UF/IFAS, Lyle Buss]
There’s no mistaking a bumblebee. They are large, buzzy, and fuzzy all over. Bumblebees are one of our most important pollinators, as they use the vibrations from their bodies to deliver buzz pollination. This type of pollination is necessary in the production of several crops, including tomatoes, eggplants, blueberries, and kiwis. Make sure to leave these bees alone while they help pollinate our plants, as females can deliver a nasty sting (or several), if threatened.
Many bumblebees, including the American bumblebee, often make use of leaf litter when building their nests. They tend to nest just above or below ground level. In Florida, queens seek a new nest site in the late winter or early spring. They then set up the first cells using wax secreted from their abdomen (less formally known as the “bumble butt”). The first cells contain only females, which assist with foraging and nest-building. Eventually, as the nest grows, males will be produced for mating purposes. Once emerged, adult bumblebees can be found all over Florida and “bee-yond” during most of the year.
Luna moth (Actias luna)
[CREDIT: UF/IFAS, Lyle Buss]
[CREDIT: UF/IFAS, Don Hall]
The majestic luna moth is a favorite of many for its ethereal, pale-green color, elegant trailing tails, and distinctive eye marks. In its cocoon form, it looks much less glamorous, often wrapped in a thin layer of leaves as a means of camouflaging its pupa. During this time, it hides out in leaf litter to avoid unwanted predation. It takes about one month from hatching for this moth to complete its development, and adults live a week, on average.
Luna moths can be found year-round in Florida, often around their host plants. The host plants of the luna moth will differ by region, but in the southern part of the United States, they are often found feeding on the leaves of hickory, walnut, sumac, sweetgum, and persimmon trees.
Common pill woodlouse (Armadillidium vulgare)
[CREDIT: iNaturalist, Daniel Das]
Occasionally called “pill-bug” or “roly-poly,” the common pill woodlouse is one of several woodlice that live in Florida. It is a terrestrial isopod, closely related to the crustaceans of the sea. Originally from Europe, this woodlouse is now distributed all around the world. While not native to Florida, this species still provides the important service of nutrient cycling.
As a detritivore, it is known for eating dead plant matter, such as fallen leaves, twigs, and bark. By doing this, it breaks down the plant matter into more usable forms, which get added back to the soil. A 2008 study showed that its dietary habits increased the local soil health of a hydric hardwood forest in central Florida.
The common pill woodlouse gets its “roly-poly” nickname from its trademark defensive behavior of rolling up into a ball when provoked. One more fun fact worth sharing is that the females carry their young in a brood pouch called a marsupium. Our native opossums, along with other marsupials, have marsupium too! Try saying that five times fast. Anyway, woodlice live up to five years and can be found throughout the state under mulch, rocks, and leaf litter.
And that’s just a smattering of Florida bugs that use leaf litter! Others include the pure gold-green sweat bee, small carpenter bee, giant leopard moth, and red-banded hairstreak butterfly. Leaving leaf litter in your landscape not only helps these bugs complete their life cycles, but it can also benefit your plants.
Free Mulch and Compost
Another popular phrase you might have heard: mulch is magic! Mulch helps protect plant roots and holds water in the soil. It can get expensive in bulk, but the good news is that leaf litter makes for a fine mulch. The Florida-Friendly Landscaping™ program recommends 2-3 inches of mulch around landscape plants. Leave a sizeable gap between the main stem or trunk to prevent rot. After leaves have served their purpose as mulch, they will eventually break down, releasing essential plant nutrients, such as nitrogen, back into the earth.
Speaking of nutrients, be very careful not to leave leaf litter near ponds, storm drains, or other entry points into our local waters. Too much nitrogen may foster unwanted algal blooms in the water, negatively impacting what lives there. Make sure any collected leaves are contained within plant beds and other areas of the landscape. This can be accomplished with a decorative border or barrier. Read our “Landscape Edging Materials” blog for ideas about how to implement an attractive edge to your beds.
If you don’t want to use leaves as mulch, they can still be added to compost as brown material.
Get Your Free “Leave the Leaves” Bumper Sticker
Now that you’ve learned about the importance of leaf litter and gotten to know some of the bugs that use it, show your support of the cause with a flashy, new bumper sticker! With all the bumper-to-bumper traffic this time of year, it’s the perfect opportunity for you to get the word out about the importance of leaf litter for our local bugs.
Fill out this form to request your free sticker, then pick it up in person at our UF/IFAS Extension Sarasota County office.
- UF/IFAS Gardening Solutions – Wildlife-Friendly Winter Gardens: https://gardeningsolutions.ifas.ufl.edu/design/gardening-with-wildlife/wildlife-friendly-winter-garden/
- Xerces Society – Leave the Leaves blog: https://xerces.org/blog/leave-the-leaves
- University of Maryland – Rake Less, See Butterflies More: https://entomology.umd.edu/news/rake-less-see-butterflies-more
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