The Yellow Garden Spider
Yellow garden spiders wear white hats.
They're big and bright and . . . well, sort of creepy looking, especially when they're "wrapping up" a pretty butterfly or moth for dinner, but despite all that, yellow garden spiders (Argiope aurantia) are great to have in the landscape.
Like toads and salamanders, yellow garden spiders are sensitive beings.Their presence in your yard is a sign that the ecology is a healthy, balanced one. They're also insect predators that can be handy to have around.
Yellow garden spiders go by many names, including black-and-yellow argiope; black-and-yellow garden spiders; golden garden spiders; golden orb-weavers; yellow garden orb-weavers; yellow garden argiope and, because of the zigzag lines (stabilimenta) in their webs, they are sometimes called writing spiders.
Yellow garden spiders catch, kill and eat a wide variety of prey, including garden pests as well as beneficials.
Yellow garden spider webs are strong enough to entangle both small and large prey like grasshoppers, moths and praying mantis. And the female spiders are strong and agile enough to subdue the large prey that they trap.
Male yellow garden spiders are about a quarter of the size of the females, which can grow to be over an inch in size with large, fat abdomens.
In this way, yellow garden spiders are comparable to praying mantis. Like praying mantis, they eat just about anything, from pests like mosquitoes, stink bugs and aphids to beneficial pollinators like bees, moths and butterflies.
If you see a yellow garden spider in your landscape, don't squash it! It's one of the good guys (most of the time). It even wears a big white "hat," its cephalothorax (head and thorax).
The egg sacs of the yellow garden spider are large & brown.
Female yellow garden spiders, webs & egg sacs are large & easy to spot. This winter, even on the bleakest days, I could see their egg sacs in the shrubbery, a welcome sign of life in the otherwise barren landscape.
In late summer, female yellow garden spiders produce three or four large, papery egg sacs.
Rounded and brown, the sacs look as if they're made from paper bags.
To keep the sacs safe over the winter, the female spiders weave them into their webs.
In our shrubbery, a female yellow garden spider wove several webs for her sacs, attaching them to stems and leaves with webbing.
The webbing not only holds the sacs in place, but it also provides them with protection from the elements and predators, such as ants, wasps and birds.
Each sac can release up to a thousand spiderlings. Only a very few of the babies, however, survive their early spiderling-hood.
Yellow garden spiders spin strong, distinctive webs.
Would you welcome the yellow garden spider in your yard?
Last year, I noticed three pairs of yellow garden spiders in our garden.
One couple set up housekeeping in a Golden Hinoki False Cypress, another in a Miss Kim lilac bush, and another in a barberry shrub.
Although I never saw the males, I knew they were there because of their webs.
Separate living quarters
Not only are male Argiope aurantia much smaller than their female counterparts, but their webs are smaller, too. In fact, their webs are actually small structures positioned near or even within the larger structure of the female's web. The females' webs are large— often more than two feet in diameter. The male spiders will sometimes spin a little web near their edges.
The males live only a year and often move from female to female. Their little webs are comparable to temporary living quarters.
Yellow garden spiders have extra claws.
Argiope aurantia are orbweavers. Like all orbweaver spiders, they are fast and prolific spinners that have three claws per foot on each of their legs. That's one more claw than most spiders have. Orbweavers use their extra claws to help them handle the threads as they spin, allowing them spin complicated webs in a few hours.
Lightning bolts web decorations
Yellow garden spider webs create zigzagging lines that look like lightning bolts down the middle of their webs. These lines are called stabilimenta, named such because they were first thought to provide structural support (stability) to the webs.
Today, however, scientists debate the purpose of stabilimenta. Do they attract prey? (Some studies show that the zigzagging lines actually reduce the number of prey captured by up to 30 percent.) Some researchers propose that the purpose of stabilimenta is to deter birds from crashing into the webs.
Yellow garden spiders bite if provoked.
Yellow garden spiders are not aggressive with people, but they will bite if they are provoked. If you grab a female near her egg sac, for instance, she is likely to inject venom into you just as she would into prey caught in her web— but with a much less devastating result, of course.
For most people, yellow garden spider bites are comparable to bee stings and mosquito bites. The damage is negligible— a little itchiness, a little redness and slight swelling.
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© 2014 Jill Spencer