Good Natured: Leave The Leaves This Fall And Save The Spring Pollinators

Good Natured: Leave The Leaves This Fall And Save The Spring Pollinators

The St. Charles Park District, in its efforts to support native pollinators, erected this bee house early this summer. It is located behind the Hickory Knolls Discovery Center. The structure was immediately adopted by a number of native bees. You can make a smaller version of this house by stuffing native plant stems into a large tin can.

  • This “Good Natured” article is written by Pam Otto, the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or

There’s no doubt, fall is upon us. The air has a crisp coolness to it, especially in early morning; the leaves are changing colors; birds are migrating through on their way to their winter destinations.

Meanwhile, lawn mowers, weed whips and leaf blowers are going full blast.

I know nearly everyone in this area likes a nice, tidy lawn. No weeds cropping up, no shaggy mowing, all leaves raked to the curb. But what I’d like to do today is to have you consider downgrading your tidiness a notch or two.

Leaves that need to be raked and bagged? Or a good insulating blanket for wintering?

Those leaves on the ground — along with native flora like cup plants, milkweeds, coneflowers and black-eyed susans — still have a job to do, even though their blooming days have long since passed. Each of them, and many others, serves as important overwintering habitat for our native pollinators: butterflies, moths, bees and wasps.

These creatures are vitally important to our existing plants, whether they are in formal gardens or casual plantings of perennials. Without pollination, these plants can’t produce the seeds and fruit they need to secure the next generation. And pollination can’t occur without pollinators.

The Big Three, as I call them — the monarch butterflies, honey bees and bumblebees — are only the tip of the iceberg when it comes to pollinators.

Here in Illinois we have more than 500 species of native bees. And few look like what we consider to be the typical bee profile — black and yellow or orange stripes, fuzzy, and of course those stingers used for self defense. Native bees can be metallic green, dark colored or similar to that typical bee profile; some don’t even have stingers.

Native bees share another characteristic that is very different from our native bumblebees and nonnative honey bees. They are solitary, semisocial or eusocial as described below. You won’t find a hive of thousands of individuals or, in the case of bumbles, a smaller underground nest. Instead, native bees fall into one of the following categories. In many cases, the bees seek bare ground — something that is rare in many areas.

The information that follows is courtesy of the Illinois Department of Natural Resources:

  • Solitary native bees make and care for their own nest. They may live with other bees of their own kind nearby (aggregations), or they may prefer to be away from all other bees.
  • Communal bees are solitary bees that use a single entrance to the nesting site, but each bee digs its own nest from that point.
  • Semisocial bees work together to raise their young with the colony only lasting one year. The mother and her offspring do not inhabit the colony at the same time.
  • Eusocial bees live in a single nest with the inhabitants sharing the reproductive and nest-making functions. These bees include a mother and her daughters in a complex system.
  • Cuckoo bees are nest parasites and rely on other bees to raise their young.
  • Bees must have a place to lay their eggs where their larvae and pupae can develop safely. They construct nests to raise their young. Some bees nest in the ground. They often choose a bare, sunny spot and dig a tunnel to raise their young. About 30 percent of native bees nest in holes. Mason and leafcutter bees use existing holes in hollow stems, dead wood and rock crevices for nest sites. Carpenter bees excavate holes in wood to form a chamber for their eggs. Other locations may be used as bee nesting sites, too.
  • In the nest, a mixture of pollen, nectar and saliva is formed into loaves. Each egg is provided with a pollen loaf in a single cell. Mud, leaf pieces and sawdust are all types of materials used to build partitions between cells. When the larva emerges from the egg, it feeds on the pollen loaf until it is time to enter the pupa stage.

We also have 2,000 species of butterflies and moths that do their share of pollinating as well. Of this number, roughly 150 species are butterflies and 1,850 species are moths. Butterfly and moth needs are quite varied, as many lay their eggs on specific plants. A little research can show you what the most popular plants, including trees, that butterflies and moths lay their eggs on. of species, one feature that all can enjoy is a mud puddle. You can let rainwater settle in a low spot for natural mud, or you can create a mud puddle by filling a large potted plant saucer with sand and soil, and then adding water.

To save any of these insects from a fate worse than a lawn mower or leaf blower, it’s critical to save some portion of our landscapes. They, the bugs, will overwinter in one of four stages, either as an egg, a larva, a pupa (read cocoon or chrysalis) or as in an adult, in a phase called diapause — the insect version of hibernation. Which stage they opt for depends on species.

Native bees tend toward the pupa option, so if their chosen overwintering site gets chopped down, it’s adios to that next generation. Mourning cloak butterflies, a personal favorite, overwinter as adults and, so long as their diapause is uninterrupted, they are usually the first butterflies to appear in this area. Their timing often aligns with the time the sap is running in maple trees, late February to early March, which is months ahead of most other butterfly species. Meanwhile, most moths are tucked inside cocoons, waiting for a warm spring day to emerge.

We should all be so lucky!

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