Magical Garden Orbs

Melissa Donahue

Fall is the time of year when we see many spiders at the park. Last week in the garden I came across this lovely spider enjoying her breakfast. I decided to get to know this spider a little better.

Marbled Orb Weaver Crab Spider

Jumping Spider Arrowhead Spider

My spider is one of more than 45,000 spider species in the world. They can be found everywhere but the poles, oceans, and high mountains.

Wolf Spider with eye shine

Photo credit Sullivan County Conservation District

Spiders are found both day and night. They are easy to find at night because their eyes shine when exposed to light light. A fun activity is to look for spider eye shine after dark. Take your flashlight out and look for glowing green dots along the side of the trail, in bushes or on your darkened porch. Those are spider eyes.

Wolf Spider with Egg Sac

Only about fifty percent of the spider species spin webs. Other spiders, such as this wolf spider, live in the ground, on plants, or under low growing bushes. These spiders are excellent hunters.

Orb Web

The spider in the garden is a yellow garden spider. Argiope aurantia. It is one of 4000 species of orb weavers.

Yellow Garden Spider

This species of spider, like all spiders, has eight legs, a cephalothorax, abdomen, fangs, and a silk spinner. Unlike other spiders, this species has a unique third claw on each leg to help spin complex webs. Spiders have from zero to eight eyes. My garden spider has eight.

Marbled Orb Weaver Spinning a Web

Photo Credit Kim Bailey

A typical orb web spider builds a web between two very strong supports. Two types of silk are used. The first, a non-sticky silk, creates the radial threads of the web. The frame of the web is made by the same silk The other spiral threads are made of a sticky silk, which is clingy. Most orb spiders eat and rebuild at least part of their web every day or night. On average it takes 30 to 60 minutes for this spider to spin its web. A yellow garden spider uses her web for a few days.

Yellow Garden Spiders on her Web

The web is almost like an extension of their bodies, used to catch meals and increase their awareness of the world around them. Orb spiders have very poor eyesight, but they don’t need to see well because of the way they use their webs. There are special lines in their webs to sense prey. When something touches these lines, the lines vibrate, and the vibrations are a message to the spider, telling it there is something in the web. The spider can tell by the way the web vibrates if the movements a struggling insect victim, or something else.

Writing Spider

Notice the zigzag in the middle of the web. The “zipper” or “zigzag” in question is called the ‘stabilimentum”. Scientists are not sure why the spiders spin these structures. One theory is it provides stability to the web. Another theory is it attracts insects by reflecting UV light. A third is it warns birds not to fly through the web, thereby preserving the web. Scientist are studying the webs to find the answer. The zigzag has also earned this spider the nickname Writing Spider.