Common Midwest Spiders

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Spiders are sometimes misidentified as insects, since they have jointed legs and exoskeletons, but spiders are arachnids, a separate class altogether. Spiders have two body regions instead of three, eight legs instead of six and usually eight eyes, not six. All spiders have fangs and can inject venom, but rarely is a spider bite a threat to human beings. In the Midwest, the brown recluse is the only commonly seen spider that poses a serious threat.

Brown Recluse

Perhaps the most infamous of the commonly seen Midwestern spiders, the brown recluse typically hides in homes in dark enclosed spaces. Also known as the violin spider or fiddler, the recluse rarely grows beyond 1/2-inches long and is mostly brown in color, although its legs are a lighter brown and its abdomen also can be yellow or green. Its distinguishing mark is its namesake: a dark brown, violin-shaped spot on its cephalathorax, the first major portion of its body. Although the Recluse only bites if it is provoked and its bite is often not even felt, its venom is particularly poisonous and can lead to necrosis--tissue death-at the site of the wound. Worse symptoms can manifest, depending on the victim's sensitivity and amount of injected venom.

Sac spiders are often seen inside and out, are yellow or light in color and grow to almost a half-inch in length. These spiders can be found in rolled-up leaves or under rocks outside, and in high corners in out-of-the-way places inside. Because they tend to hunt at night, they are most active then and are often blamed for most of the bites that occur in the house. Like that of the brown recluse, the venom of the sac spider can cause necrosis, although it is rarely severe and typically does not leave a large wound.

Wolf spiders usually stay outside under rocks or on the ground and have bodies between 1/4- and 3/4-inches long, although their leg spans can reach several inches. They get their name from their hairy legs and brown to grayish coloring with white markings. Although they move quickly, can appear aggressive and have long fangs, they pose no real threat to people, although their bites can cause swelling and redness. The eyes of these large spiders are what you often see if you shine a light into your back yard and see little reflections.

The orb-weaver spiders build the wheel-shaped webs seen in gardens, fields and forests, and are rarely seen inside. They have eight same-size eyes, hairy legs and bulging abdomens. There are many types of orb weavers, ranging in color and size, but two often seen in the Midwest are the black and yellow argiope, or garden spider, which grows to one inch long, and the barn spider, which is brown and grows to nearly an inch.

Jumping spiders are between 1/5- and 1/2-inch long and found inside and outside the house. Unlike some of their relatives, they are active in the daylight and can often be found where the sun hits them, such as in windows. They are typically dark with white marks, have two large center eyes of their eight and, as their name suggests, can leap several inches to attack.