Orb Web Weavers
The Great Outdoors | August 24, 2017
By Jackie Scharfenberg, Wisconsin Department of Natural Resources
WELCOME TO MY WEB!
I am a female yellow garden spider (Argiope aurantia), probably the largest orb web-building spider in North America. In late summer I reach my full size with a body measuring 0.75-1.1 inches. I have a leg span up to 2.75 inches. The guys only grow to a quarter of my size.
We sport bright yellow bands separated by thin black stripes that meet in a black center line across our oval-shaped abdomens. Our long legs are mostly black with reddish-yellow bands near our bodies. Silvery gray hairs cover our gray-yellow carapaces while our sternums are black with a yellow middle stripe. Males are smaller and appear more brown.
WEB WEAVING
I begin web building by letting out a few strands of silk that merge to form one strong strand that floats in the wind until it attaches to a plant stalk. This starts the bridge lines, and other scaffolding that supports the framework of the web. Next, I construct a hub with threads radiating from it like spokes of a wheel. Starting from the hub, I spiral clockwise outward stitching sticky silk to the spokes. This sticky silk works to catch my prey of flying and jumping insects. Finally, I add a heavy zig-zag stabilimentum in the center. Some think I use the stabilimentum as camouflage. Others think it gives off ultraviolet light that attracts insects, or prevents birds from crashing into the web. It takes a few hours to complete the web. Each night I eat the sticky spiral and re-weave a new one in the early morning, since I do my hunting during the day. Some scientists think I eat my web to recycle the materials and consume minuscule insects and organic matter.
MY EATING HABITS
To capture my prey, I hang upside down in the center of my web. I feel for vibrations of my stuck prey. Once an insect gets caught, I shake the web making sure it’s super-stuck. Then, I crawl out to inject my meal with paralyzing venom and wrap it in silk to save it for later. Since I don’t have teeth, I have to turn the insides of my prey into a slurpy and suck it out.
MY DEFENSE
To protect myself from predators, I vibrate my web. This makes both my web and I look bigger. This also helps to blur my location. If that fails, I drop down to the ground using a strand of silk. If a human picks me up, I may bite in defense, but usually I am pretty mellow. Even though my venom kills insects, for most people, it causes a reaction like a bee sting.
OUR WEBS
This fall you can look for our big circular orb webs in carefully chosen spots in gardens, fields, roadsides, yards, and near houses. Our webs can be found from southeastern Canada throughout most of the United States into Central America. We females remain in one spot for most of our lives, but we may move our webs early in the season to find a better hunting or protected spot. Males roam around looking for females and build small webs near or within females’ webs.
PHOTO BY Ingrid Taylar.
