Orb-weavers are cool, once I get past the terror

I don’t know what my deal is with spiders lately, but here’s another cool one I found in a web outside my house. I’ve seen these things in gardens, near the edge of my yard and in the bushes while picking raspberries, but never near a house. It kind of stands out, so I was compelled to learn some more about this bright spider.

Photo by Aislinn Sarnacki. A yellow and black garden spider waits in its web outside my home in the Bangor area on Aug. 7, 2012.

The black and yellow garden spider is the species Argiope aurantia but its also known as writing spider or corn spider. Although they appear alarming, they are not considered dangerous. They may bite when harassed, but there venom doesn’t cause any problems for humans. As I noticed, they do prefer areas around flowers and plants. They also like the sun, so that’s probably why it situated itself on the sunniest side of my house. Their beautiful web is called the Orb web, and their family is called Araneidae, also known as the Orb-weaver spiders. Orb-weavers have eight similar eyes and their legs are hairy or spiny.  

The yellow and black garden spider builds an orderly orb web — a flat, sticky spiral of capture silk. The web is distinctive: a circular shape up to 2 feet in diameter, with a dense zigzag of silk, known as a stabilimentum, in the center. The purpose of the stabilimentum is disputed. It is possible that it acts as camouflage for the spider lurking in the web’s center, but it may also attract insect prey or even warn birds of the presence of the otherwise difficult-to-see web. Only spiders that are active during the day construct stabilimenta in their webs.

The female spider, typically 1 1/2 inch long, is much larger than the male spider, typically 3/4 inch long … so I think I have a female spider by my house. She’s big and bright. However, it is said that the zigzag down the center of the web may be produced by the male — so maybe I’m wrong or maybe there is a male nearby, or maybe that zigzag theory is wrong.

If you look at the photo closely, you’ll see that her head is small and tipped with silver hairs. Each of her legs have three claws on the end to help her with building her web. If I watch closely, I might see her catch flying insects — aphids, flies, grasshoppers, wasps, and bees. When an insect lands in her web, she might start shaking the web to get the insect more ensnared. She will then bite them, injecting venom, and wrap them up in a cocoon to eat a few hours later.

Pretty cool. I guess I’ll let her stick around, though she might be more comfortable in my flower garden.



Aislinn Sarnacki

About Aislinn Sarnacki

Aislinn is a Bangor Daily News reporter for the Outdoors pages, focusing on outdoor recreation and Maine wildlife. Visit her main blog at actoutwithaislinn.bangordailynews.com.