GARDEN SPIDERS COMMON TO ALABAMA

In Focus – By CR Brown

Imagine walking along a wooded path when suddenly you come face-to-face with the critter pictured above. That critter is Argiope aurantia, otherwise known as the Black and Yellow Garden Spider or Corn Spider. It is also known as the Banana Spider or Writing Spider in some circles. Here in the Wiregrass (south-central Alabama), the folks simply refer to it as a harmless Garden Spider. This particular species is common to most areas of North and Central America. The typical male ranges in size from 5 to 9 mm, while the female is much larger at 19 to 28 mm. Some can be larger still.

Look for Garden Spiders to build a circular web 24 inches in diameter anywhere from two feet to eight feet off the ground. The web will usually be located near an open area, where it will likely have access to sunlight throughout a good part of the day. Once the web is constructed, the female will rarely move to another location during her lifetime.

The first step in the construction of the web consists of strategically placing four or five anchor lines that are attached to points three or more feet apart. Those anchor lines intersect, forming the center of the soon-to-be-constructed 24-inch circular web. At the heart of the web is a dense zigzag of silk called stabilimentum measuring approximately 1 inch by 4 inches. The stabilimentum acts as camouflage for the host spider but also as a warning device to birds winging their way through wooded areas.

Hanging head-down in the web, the female Garden Spider waits for unsuspecting prey to become entangled in her handywork. If she feels threatened, she may drop to the ground where she can hide until the danger passes.

Amazingly, the female spider purposely rebuilds her inner web on a daily basis. She consumes the silk lines making up the inner web every evening and then rebuilds in the early morning. It is believed that tiny insects and other nutrients too small to see with the naked eye are captured in the webbing, which provides the spider a steady dietary source.

Garden Spiders bring fourth their young only once yearly. After seaching out a prospective female, the male spider will build a small web next to his mate to be. He will then court the female by plucking the taunght web strands much like a guitar. However, he remains vigilant while approaching the female, keeping a safety drop-line at the ready, just in case the female goes on the attack. The male dies shortly after mating at which time he is often eaten by the female.

After placing her eggs in sacks, usually numbering 1-4, the female Garden Spider becomes more frail as the weather turns cold and will die on the arrival of the first frost.
The egg sacs will hatch when spring arrives, releasing potentially thousands of spiderlings. Most of those will remain in the local area, while others will deploy a single strand of silk that will act as a wind sail, carrying them to other areas.

The female Garden Spider pictured above resides above a walking trail in Heath, Alabama.