Let’s see…what’s the best way to put this?
I’ve got worms.
Now, before you start thinking that I’ve been eating raw meat or playing in a dirty sandbox, let me hasten to say that you, or someone you know, no doubt has worms too.
Of course the worms we’re talking about here are the kind you find in your lawns and gardens, or slithering across your driveways and sidewalks. They’re earthworms and, this time of year, they’re everywhere.
Springtime equals worm time, much to the horror of the anti-worm crowd. Every spring when it rains, my friend Lisa—in her words—gets “grossed out” about all the worms on her driveway. “Why do they come all over the sidewalks, driveway, squiggle under my garage door, only to dry up and die?” she asks. “Are they just stupid?”
It’s true, no one would accuse worms of being rocket scientists. Their brains are but a small collection of cells designed to direct the worm’s response to light—that is, to move away from it. For it is light, or rather the light’s intensity, that often determines whether a worm will live to squiggle for another day—or not.
Bright, sunny days are big trouble for worms. Sunlight and warmth dry out a worm’s delicate skin. “So?” you might be thinking, “Sunlight dries my delicate skin too.” But for worms, desiccation means devastation. An earthworm’s skin is also the way it “breathes,” taking in oxygen through porous membranes; in order for oxygen to diffuse into the worm’s body, its skin must remain moist.
Ergo, the best time to go traveling, when you’re a worm, is when it’s raining. Up from their burrows they come and off they head to points perhaps several feet away…until they encounter pavement. There, unable to burrow, the worms frequently languish on the surface.
They may become prey for a hungry predator; my friend and coworker Mike Horton once watched a young red-tailed hawk eat his fill of worms stranded in the preseason emptiness of the park district’s Splash Park. Or, as my friend Lisa well knows, they may dry up and die.
Many folks, when they see masses of worms marooned after a rain, figure that the little critters left their burrows because they would otherwise drown. Not so. Worms can extract oxygen from water as well as air, so being underwater for awhile usually isn’t a problem. It’s the moisture above ground, and the low light levels, that have the worms up and about when it rains.
While we’re on a roll, let’s dispel a couple other misconceptions. One pervasive myth is that if you cut a worm in two, both halves will survive. Again, not so. The two pieces may exist for a few hours, tops, but in the end both will die.
And finally, there’s the commonly held believe that worms are all good. They aerate the soil, which gardeners everywhere appreciate. And they also produce castings, nutrient-dense droppings that help enrich the soil. However, these benefits are only half the story.
The earthworms we have in northern Illinois today are, by and large, exotic species brought here from Europe. Any native species that might have lived in this region were wiped away by the glaciers thousands of years ago. What we have in our lawns and gardens (and on our driveways and sidewalks) are a mish-mash of species whose ancestors hitchhiked to this country in shipments of soils, plants and fishing bait.
Though relatively harmless in our suburban landscape, these foreigners can be troublesome in native forest ecosystems. They speed up the process of decomposition on the forest floor and have been blamed for a decrease in plant diversity. In fact, the problem is so severe that a monitoring program, the Great Lakes Worm Watch, has been organized to keep an eye on earthworms and slow their progress.
Have you got worms? Chances are, you do. Learn all about them at www.greatlakeswormwatch.org.
Pam Otto is the manager of nature programs and interpretive services for the St. Charles Park District. She can be reached at potto@stcparks.org or 630-513-4346.