Get to know your suburban spiders
It's hard to believe, but there are just a few more days of summer left. The days are getting shorter and there's a notable a shift in the natural world.
While I find it bittersweet to say farewell to summer, I also revel in this transition time for the creatures it brings. Notably, spiders.
If you're wrinkling your nose and thinking, “Eww!”, hang on. Put aside the “yuck” response for just a minute, and you may be awed by the beautiful, strange, and incredible spiders of the season.
Orb weavers are the stars of the spider world this time of year. This large group comprises spiders that are both artists and architectural engineers, creating magnificent spiral webs of silk.
One of the most stunning of the orb weavers is Argiope aurantia. I call it A. aurantia, or just aurantia for short, but this species goes by several common names — garden spider, black-and-yellow Argiope, writing spider and, for some reason, only in our area, it's known as the banana spider.
With bold yellow and black coloring, A. aurantia spiders are both cryptic and conspicuous at the same time. In a prairie of yellow flowers on dark stalks, a yellow and black creature can be hard to spot at first. Once you see an aurantia, though, you'll think, “How did I not see that before?”
The females are big — the body alone can be over an inch long. Add long legs to that and you've got a formidable spider. Male aurantias, however, are puny by comparison (about a half inch long) and less colorful than the females. Their role seems insignificant, but, of course, the males are needed for at least a brief period of time in the spider year.
When people recover from the shock of seeing a big female aurantia, they immediately ask, “Is it poisonous?” No! This is true of all of our native orb weavers. Their venom serves only to paralyze their prey. They're very shy, and you'd have to go out of your way to get bitten by one.
At the slightest disturbance, an aurantia will quickly drop to the ground and disappear. To get even a quick photograph, you have to be stealthy — and patient.
Next up on the spider stage is Araneus marmoreus, the marbled orb weaver. It's also called the pumpkin spider. Both nicknames fit, as the large, round abdomen is marbled and it can be as orange as a pumpkin (although there's lots of variation in color in this species).
These spiders are pretty widespread, living in varied habitats from woods to prairies, along streams, among weeds, and in flower gardens. I've found them under the eaves of the house and on my porch steps.
Marbled orb weavers, like Argiope aurantia, are not poisonous to us. They have little to no interest in humans, and biting a human would be a colossal waste of venom — an expensive resource to produce. An orb weaver reserves venom for its prey.
A difference between the marbled orb weaver and Argiope lies in its escape tactics. While the latter bails from the web when frightened, a marbled orb weaver skedaddles along a silken escape route that leads her right into a safe, silken refuge in a curled up leaf.
I roused one out of its bunker the other day, and she instantly took the next safety precaution, assuming the spider version of the fetal position. She seemed to be thinking, “Maybe if I roll up in a ball no one will see me!”
Orb weavers capture their prey in their sticky webs, but some spiders get meals without building webs. Wolf spiders, for example, don't build nests. They use silk only to make nests and hiding places. These hairy beasts don't wait for prey to stumble into a web, they run after them. With amazing speed, wolf spiders are masters at overcoming unsuspecting victims.
Spiders can have up to eight eyes. Even though orb weavers have the classic eight-eyed look, their vision isn't so great. It doesn't need to be, because they detect prey by vibration and chemical cues. Wolf spiders, by contrast, have to have sharp vision. Their eyes are arranged in a unique pattern, which kind of looks like a reverse smiley face.
Unique among arachnids, wolf spiders hold egg sacks in their spinnerets. When the spiderlings hatch, Mom carts them around on her back. This is often what catches my eye. If it weren't for the egg sacks and tiny wriggling spiderlings, I'd rarely notice wolf spiders on the ground.
Another group of spiders in our area is the crab spiders. These awesome little creatures rely on camo and ambush to take down prey.
Flower crab spiders are usually white or yellow, making them blend into the background of their flower perch. Bark and ground crab spiders are dark colored to blend in with their background.
Waiting patiently (or not), a crab spider is always poised to pounce the instant an insect meal comes its way.
As summer turns into fall, spiders of all kinds abound. Watching them is to see the intricacies of the web of life. Predators, prey, adaptions to survival, habitat variety — it's all there. I encourage you to take a look at spiders, even if only the ones on your porch.
You'll see astonishing creatures, and if you're lucky you'll catch some drama. You may even get hooked, as I am, on hunting spiders. Hunt only with a camera for these magnificent eight-legged beasts.
Share your spider pics and stories with me at blainevalerie@kaneforest.com.
Learn more about spiders
Want to learn more about spiders?
• Sign up for our naturalist guided program, “The World of Spiders,” from 10 to 11 a.m. Saturday, Sept. 29, at Rutland Forest Preserve, 41W230 Big Timber Road, Hampshire. All ages are welcome. The program is free, but registration is required. Call (630) 444-3190 or email programs@kaneforest.com.
• An excellent resource is “Common Spiders of the Chicago Region” produced by the Field Museum: <a href="https://fieldguides.fieldmuseum.org/sites/default/files/rapid-color-guides-pdfs/390_1.pdf">https://fieldguides.fieldmuseum.org/sites/default/files/rapid-color-guides-pdfs/390_1.pdf</a>.
Another go-to for insect and spider identification is <a href="http://www.bugguide.net">www.bugguide.net</a>.