The Argiope aurantia (black and yellow garden spider) has distinctive yellow and black markings on the abdomen with a mostly white head and chest. Males range in size from 0.20–0.35 inches and females range from 0.75–1.10 inches and can be up to 2 inches across. They are found throughout the continental United States, Canada, Mexico, and Central America.
The spider eats flies, bees, and other flying insects that are caught in the web the female spins. The web can be as much as two feet across. When threatened, she will shake the web like a trampoline as a warning to not come near. If the warning is not heeded, she may bite. Her bite is harmless, much like a bee sting, however, if you are allergic, you should seek medical attention.
These spiders have amazingly efficient, even miraculous, chemical factories within their little bodies. They are capable of making up to seven different types of webbing and they have an inboard chemical plant that produces chemicals necessary for their survival.
The web is circular shaped made of sticky strands that are suspended on non-sticky spokes, which she uses to run along the web without getting stuck. The sticky webbing serves to catch an unsuspecting meal. It has a distinctive and conspicuous dense white zigzag structure in the middle called the stabilimentum. Because of this, they are often called zipper spiders. However, the exact function of the stabilimentum is unknown. Some speculate that since the web is very big, it might alert birds so they don’t fly through it.
When a bug is caught, the spider emits sheets of webbing to encircle the bug. Somehow it knows when to use sheets versus the fine strands of webbing that make up the web structure. All spiders are carnivores and prey primarily on insects, and will eat anything that doesn’t tear itself loose from the web. These garden spiders know that they have a potential meal when they feel vibrations in their web.
This garden spider mates in late summer or early fall. The male builds a small web near or inside the female’s web. He courts her by plucking strands on her web. Spider mating doesn’t always turn out so well for the male of the species, so when he approaches her, he comes prepared with a safety drop line at the ready, just in case she does not see him as the spider mate of her dreams and attacks him. However, once he is assured of her acceptance, he uses the two palpal bulbs on his pedipalps (located in front of his front legs) to transfer sperm to her. Once he has delivered both bulbs, he dies; and sometimes, she eats him.
The female lays her eggs at night on a sheet of silky material of her making, then covers them with another layer of silk, and finally a protective brownish silk which she then forms into a round, brown cocoon, like a ball with an upturned neck. This ball is about an inch in diameter. When depositing the eggs in the sac, she dusts each egg with a fine powder to keep them from sticking together. This is one of the chemicals made in the chemical factory within her body. That may not seem like much work, but considering that each female produces one to four sacs with as many as 1,000 eggs inside each, that would be quite a job.
The egg sac, or shell, normally stays intact all through the winter with the baby spiders emerging in the spring. As these spiderlings begin to grow inside this shell, they soon must exit it or die. At just the right time a fluid, called moulting fluid, is deposited at just the right place and a trap door is made in the shell that allows the spiderlings to crawl out. This is yet another chemical that is made in its chemical factory. This moulting occurs two or three times as the spiderlings are growing to adulthood.
As the spiderlings exit the egg sac in spring, some of them take up residence close to home, while others shoot out a strand of silk that is caught by the breeze, carrying the spiderlings to a distant new home.
What amazing little creatures these spiders are!!
They make seven different strands of webbing with the knowledge to know when and how to use each one of them. They make the powder that prevents the eggs from sticking together and make moulting fluid, with the knowledge of exactly when to deposit it inside the sac to make the trap door so the spiderlings can escape.
One has to ask if this could have evolved by chance over thousands of years. No, this is another creature that shows that it had an all-wise Creator who planned with infinite knowledge and care for all of its needs. What a wonderful Creator God we serve!
Sources: Incredible Creatures That Defy Evolution, Volume 1 by Dr. Jobe Martin; NC State Extension Publications; wikipedia.org/wiki/Argiope_aurantia; nwf.org/Educational-Resources/Wildlife-Guide/Invertebrates/Yellow-Garden-Spider; entnemdept.ufl.edu/creatures/MISC/SPIDERS/yellow-garden-spider