On the web: A look at 2 garden spiders you may find in your yard

When I see a garden spider, l recall a fellow graduate student who I came to know while doing owl research in Minnesota. On occasion, I would drop by her office which she shared with her husband, a professor, and a jar of live black widows. Keep in mind that neither her nor her husband's research concerned spiders. I guessed she just liked their company.

To be honest, l was glad my office was one floor up. It's not that I'm phobic or anything. I've held all of the “big three” of creepy-crawlies: bats, snakes and spiders.

The biggest spider I've held was a tarantula that, with all of its fur, felt like a long-legged hamster.

Be that as it may, if you are concerned about poisonous spiders, the “look but don't touch policy” is the safest. If you follow this practice, the odds of being bit by one of Illinois' few poisonous spiders, the brown recluse or black widow, are virtually nil. They are both shy and timid spiders that only bite if squeezed or held against the body in some way. With that poisonous spider disclaimer out of the way, let’s get back to the story.

Based on late summer calls received here at Stillman, people are or will be discovering garden spiders in their yards and near their places of business. The dramatic size and colors of these spiders identify them as members of the Argiope genus. Of course, a variety of spiders are loosely referred to as “garden spiders.” We’ll take a closer look at two members of this genus commonly found in Illinois.

These Argiopes would be the black-and-yellow and the banded garden spiders. Each has an inch-long body. Add on their long legs, and the spiders are approximately three inches in length. Besides being big on their own, they weave a large, Halloween-style orb web.

The web, which hangs vertically, is usually placed in open areas between tall grasses or weeds. The black-and-yellow Argiope tends to build its web higher above the ground than the banded garden spider. If the web spinner is disturbed, it often drops to the ground.

So as you approach a web, you may miss the spider. However, a close look at the web can reveal the telltale signature of its occupant; a white zigzag band runs a short distance, up and down, from the center of the orb.

If the spider remains on the web, it typically positions itself upside down with its eight legs paired up. If you imagine the face of a clock at the center of the web, the two back pairs of legs are pointing at 1 and 11 while the front pairs point at 5 and 7.

The adult Argiopes are generally not visible until August or September, which explains the timing of the calls to the nature center. As the females are larger and more colorful than the males, they are the ones you are likely to see.

Now, if you're looking at the topside of the spider, the head (technically speaking, it's the cephalothorax) of the black-and-yellow garden spider is gray and yellow with a fine coating of silvery hairs. The same area on a banded argiope is yellow with grayish white scales. The most obvious difference between the two is the pattern on the top of their abdomens.

These abdomen patterns have earned the Argiopes their names. The banded garden spider displays a series of alternating silver-and-yellow and black bands.

The black-and-yellow garden spider has a wide black area running down the center of the abdomen. The sides are marked with large yellow bands, appearing like irregular blotches, separated by narrow black stripes that connect back to the dark median area. In overall shape, the banded argiope's abdomen comes to more of a point than does the black-and-yellow's abdomen.

These spiders' long legs are also brightly colored. The banded garden spider's legs can range in color from orange-yellow to brown with dark spots and rings. The black-and-yellow's legs are, well, black and yellow, although segments of the legs can also be orange or reddish.

A spider's markings aside, it is the symmetrical beauty of a spider's web that often catches the eye. Late last summer, I saw such a creation, dripping with beads of morning dew. It glistened in the sun like a web of jewels. As I enjoyed this scene, which was destined to quickly change as the heat of the day evaporated the dew, I thought of the following passage by Elwyn White:

When I get sick of what men do,

I have only to walk a few steps in

another direction to see what spiders do.

Or what the weather does. This sustains

me very well indeed.

I encourage you to walk a few steps in another direction and see what garden spiders do.

• Mark Spreyer is executive director of the Stillman Nature Center in Barrington. Email him at stillmangho@gmail.com.