Spiders are not actually insects; they have too many legs. They are arachnids - in the same family as scorpions and ticks. All spiders consist of two body parts. The front section contains the eyes, stomach, fangs, and brain. The back half, the abdomen, is where the silk glands are held. This silk is used for building webs, climbing, trapping prey and building egg sacs. Spiders are plentiful throughout the world, but there are a few common and large varieties living in Illinois.
Nursery Web Spiders
Nursery-web spiders are large spiders that can have a body length of up to one 1 inch. These spiders shed their skins as they continue to grow. The color and patterns of nursery web spiders vary but tend to be in the brown, black or yellow families of color. Females will carry their egg sacs in their jaws in the summer. Nursery web spiders are active hunters. They do not wait for prey to fall into their webs, but search the wooded grounds for worms, insects and other spiders for food.
The wolf spider can grow between half an inch to 2 inches in length. They are brown or gray and have stripes on their backs. These spiders are very hairy, thus contributing to its name. They have unique eye arrangements: four small eyes on the bottom, two large eyes in the middle and two medium eyes on top. These spiders are also hunters and will search for food day and night. Wolf spiders are venomous but not lethal. They are also not aggressive. Oddly, wolf spiders are cannibalistic. Wolf spiders will prey upon older females in order to improve chances of reproductive success.
Daddly Long Legs Spiders
Daddy long legs are an extremely common type of spider in Illinois. While their bodies are not very big, their legs are often very long by comparison. They are pale yellow-brown, and prefer low-light locations where they are not likely to be disturbed. They are web-makers and usually design them loosely and large. Mother daddy long legs watch over their newly hatched young for over a week before they leave the maternal web. These spiders are likely to be found in dark corners of houses such as attics or cellars.
Cobweb spiders are also called common house spiders because they often search out human homes in which to live. They build very organized, circular webs and will eat nearly anything small enough to be trapped in their webs. These spiders have poor vision and rely on finding trapped prey by feel. These spiders are generally harmless, though the venomous black widow is a subspecies of this spider.