Wilderness Underfoot: The black and yellow Argiope

StoryImage( ‘/Images/Story//Auto-img-112672476025841.jpg’, ”, ‘Argiope aurantia – otherwise known as a garden spider, black and yellow garden spider, golden garden spider, writing spider, golden orb weaver, and St. Andrew’s cross spider. Argiope is pronounced ar-gee-ope.’);

Throughout autumn, this attractive spider can be found on large glistening webs stretching across tall plants in gardens and meadows

The Argiope is a bold spider in every sense of the word. The female is large, with long legs and an egg-shaped body that grows a full inch in length. Her abdomen is velvety black with striking yellow splotches. Not inclined to burrow and hide like many other spiders, both male and female Argiopes build their extensive webs in full sunlight. These webs span up to 4 square feet, and the spiders are so brazen as to rest right in the middle. If a web is disturbed by a creature too large to be a meal, the Argiope will madly rattle itself and the silk lines until everything becomes a blur.

These are our largest spiders. They spend the summer feeding on insects that walk, jump, fly or fall into their sticky webs. The female can take prey that is up to twice her size. Once an insect is trapped, she rushes to it and wraps the poor creature in a cocoon of silk. Then she delivers a poisonous bite. Her venom has two functions: first, it paralyzes the prey, and then it turns the insect’s insides into a slurpy goo that she can suck out whenever she’s hungry.

Building the web is an engineering feat that begins with a silk that is stronger than steel, yet light and elastic. This is the toughest fiber known on earth. The web is a thing of amazing beauty, with long spokes woven together by cross lines like a fishnet. It is finished with a series of large “x’s,” which are thought to reflect UV light to attract insects. Strangely, she consumes her web each night and then spends hours building a new masterpiece.

Like other spiders, the female Argiope feeds on the male after mating. But unlike other spiders, she doesn’t hold any culpability for murdering him. She’s completely innocent. Unfortunately for the male Argiope, he simply drops dead after the act is finished.

The female then makes one, two or three papery egg sacs filled with as many as 1,400 eggs each. The sacs are attached to a tall weed, and she guards them until a cold frost kills her. Her offspring spend the late fall and winter in the sacs, feeding on one another until spring, when the survivors emerge. Tiny Argiope spiderlings are able to survive winter temperatures of 20 degrees below zero or colder, thanks to natural antifreeze (polyhydric alcohols such as sorbitol, glycerol, and mannitol) in their bodies.

From the Sept. 14-20, 2005, issue

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