It’s that time of year! The crispy edges of summer, back to school, football, AND adult Argiope aurantia season. You may know her as the banana spider, garden spider, black and yellow spider, Steelers spider, or some other nickname, but we’re all talking about the same lady. Yes, the spider you notice is the female of the species. Males are much smaller and not as conspicuous. These guys stand out due to their size, color, and the fact that they’re active during the bright daylight.
When I was a kid, finding one of these spiders was a magical, amazing, wonder. I seemed to stumble upon them, usually in mid-sprint, playing tag, release, or amidst a “seriously dude, I had dibs on that wood for my shack first” neighborhood fort battle. The sight of a “banana spider” would stop me in my tracks. It was newsworthy enough to actually call a temporary truce and gather friends (and enemies) to “come check this out!” The large, intricate web and the sheer size of the spider was such a find! It fascinated and scared us at the same time. It was far too big to even attempt to catch , what with that giant sticky web acting as a protective force field. And if the spider moved, well, that would usually send a few of the gang screaming home, but some of us would stay until we realized the kids that left were probably stealing our wood…
The adult females that we see at the end of summer, beginning of fall, are the full grown, adult survivor spiderlings of last year’s egg sac. So last summer, at this time, an an egg sac was created containing 400-1200 individual eggs. Adult females can produce up to 4 egg sacs in its lifetime. More info at spiders.us.
YES, that’s a lot of little babies, but the reason there are so many offspring is because most of them will die at some stage in their life cycle. It could be death by parasite in the egg sac, predation on it’s first jaunt outside, a bad molt, cannibalism, environmental factors, curious kids with sticks, or simply hanging at the wrong place at the wrong time. The odds are stacked against them.
Once they hatch some time in autumn, they are dormant until spring in the safety of the egg sac. In the spring and early summer, the spiders look nothing like the adults we’re so used to seeing now. They are smaller and sometimes silver or greenish.
That “zipper” or disc that you may notice in the center of their webs is called a stabilimentum (stabilimenta pl.). The stabilimenta in juvenile A. aurantia webs tend to be wider and disc shaped compared to the adult “zippers”. Scientists are still trying to figure out the function of stabilimenta, whether it has something to do with UV light attracting bugs or repelling harmful sun rays, no one knows, but it IS interesting how the stabilimentum changes as the spider grows.
As the spider eats and avoids being eaten, it grows, and molts until it becomes the mature, giant, beautiful females we are seeing now. These are the hardy survivors! It is mating time and these robust spiders have a lot of work to do to fulfill their missions. Males will die soon after mating and the females will die by first frost. If you find an egg sac, leave it where it is. There is no need to take it indoors unless you want the spiderlings to disperse early. (Yep, I’ve done that.) These guys know what they’re doing and are equipped to survive the winter, come what may.
Argiope aurantia spiders are harmless. They are not even aware of us humans until we start messing with their webs. They will do everything they can to escape a threat with biting being a last resort. Plus, you’d have to position yourself in such a way to be bitten. They’re not going to purposely crawl on you unless it seems like the best escape route. If all of those worst case scenarios DO happen, you’ll get nothing more than what feels like a wasp sting and the spider will again try to flee. Wasps CHASE you, so I’d be way more afraid of those black and yellows! There is no reason to feel threatened by our late summer neighbors!
So as the our days shorten and cicadas buzz their hazy song, the Banana spider heralds the last “WOOTS!” of our summer. To me, they symbolize the last bike race before the streetlights come on, the quiet solitude in a sunny field of goldenrod, and the finishing touches of a well-built fort!