Pest Identification And Information

Jumping spiders are common spiders outdoors and indoors. They are active during the day and are often found around windows, ceilings, walls, and other areas exposed to sunlight. Jumping spiders are generally small to medium-sized (about 1/5 - 1/2 inch long) and compact-looking. They are usually dark-colored with white markings, although some can be brightly colored, including some with iridescent mouthparts. These spiders move quickly in a jerky, irregular gait. They get their name from their ability to leap on their prey, often jumping many times their own body length. Like most spiders, jumping spiders have eight eyes, of which the two middle eyes are particularly large. Jumping spiders have the best vision of spiders, seeing objects up to 8 inches away.

Wolf spiders are common spiders outdoors and are occasionally seen indoors. They are moderate to large-sized spiders (1/4 - 3/4 inch long). Wolf spiders are found on the ground or under stones in a wide variety of habitats, such as forest floors, grassy meadows, swamps, and bogs. Some even like to live underground. They commonly hunt during the day or at night when it is warm. Wolf spiders are dark-colored, usually brownish or grayish, with white markings.

Fishing spiders, also known as dock spiders, are typically seen around ponds, swamps, slow-moving streams, and nearby vegetation. They may occasionally be found indoors. Fishing spiders are the largest spiders in the Upper Midwest (1 inch long). With legs spread out, some fishing spiders cover as much as 4 inches. They are generally dark-colored, usually brownish or grayish, with white markings. Fishing spiders can "skate" across water and can dive underneath to capture prey. In addition to insects, fishing spiders can also catch tadpoles, small fish, and other small vertebrate animals.

Sac spiders (also known as two-clawed hunting spiders ) are common spiders on foliage or on the ground, and can be commonly found indoors. They are small to medium-sized spiders (1/5 - 2/5 inch long) and are usually yellowish or light-colored. Although sac spiders do not construct webs, they do build retreats from silk. Outdoors, they usually roll up leaves into a tube, or may construct a retreat under stones. Inside buildings, sac spiders are found in retreats in a variety of places, including high up on walls near ceilings.

Crab spiders are common spiders outdoors, but are not usually seen indoors. They are small to medium-sized spiders (1/10 - 2/5 inch long) ranging in color from yellow or red to brown or gray. The first four legs of crab spiders are crab-like, being held out to the sides. They are also usually longer than the back four. Crab spiders can walk forwards, sideways, or backwards. While many hunting spiders actively pursue prey, crab spiders wait motionless and ambush insects that pass closely by. Outdoors, crab spiders are often found on flowers but are also seen on stems or leaves.

Gnaphosid spiders are common spiders outdoors. A specific gnaphosid spider known as a parson spider is occasionally seen inside. The parson spider is a medium-sized spider (1/2 inch long) with a brownish body and gray abdomen with a white band running down over half the length of its abdomen. Parson spiders hunt at night. During the day, they are usually found outdoors under stones or loose bark in silken retreats. Indoors, they hide under objects or in cracks or crevices.

Comb-footed spiders, also known as cob- web spiders, are very common spiders outdoors and indoors. They are small to medium-sized spiders (about 1/8 - 3/8 inch long). Comb-footed spiders are usually brownish or grayish. They build irregular webs in many places, including wood and stone piles and in quiet areas of buildings, such as basements. A common type of comb-footed spider found indoors is the house spider (figure 7). It is grayish to brownish with chevron-like markings on its abdomen and a body length of over 1/4 inch.

Orb spiders are common spiders outdoors near buildings, but are usually not found indoors. They range in size from small to large (1/8 - 1 inch long) and are found in a variety of colors, with some being brightly colored. Orb spiders have large, swollen-looking abdomens, including some that are oddly shaped. They make the classic round, flat, wheel-like web familiar to most people.

The black and yellow argiope spider also known as the garden spider is familiar to many. It is large (up to 1 inch long) and brightly colored black and yellow. Another common orb spider is the barn spider. It is large (4/5 inch long) and brownish in color.

Brown Recluse Spider, The brown recluse spider, is common outdoors and indoors in the southern and central United States. It is uncommon to extremely rare in the Upper Midwest. Only one specimen has been recorded in Minnesota (1953, Lake County). Only two specimens have been recorded in Wisconsin in the last 25 years. Brown recluse spiders have been reported in several widely scattered sites in southern Iowa since 1969. Specimens have been retrieved and confirmed from only twelve counties.

The brown recluse spider is nicknamed the fiddleback or violin spider because of the distinctive dark violin-shaped marking on top of the front body section. Notice the neck of the violin points toward the rear. The brown recluse is unusual in having six eyes instead of the usual eight. The spiders are tan to dark brown and nearly ½ inch in body size. Recluse spiders avoid areas where there is human activity, and prefer closets, guest rooms, basements, and attics. They frequently inhabit shoe boxes, clothing and furniture. These spiders are most active at night and feed on silverfish, crickets, and other insects. Most people are bitten on the hands or feet when they are handling infested items.

The bite of the brown recluse spider is usually painless. However, localized burning sensation often develops within the first hour and during the next 6-12 hours, a small pimple or blister forms. The surrounding tissue begins to darken and take a raised appearance. The venom of this spider can cause extensive tissue damage (necrotic reaction) and over the next 10-14 days, a sunken, open, ulcerated sore up to several centimeters in diameter. It normally takes 6-8 weeks for a brown recluse spider bite to heal. A large sunken scar may persist that requires surgery to repair. Not every brown recluse bite results in ulcer formation. In rare cases systemic complications such as liver or kidney damage result.

See your physician or emergency room as soon as you suspect a brown recluse spider bite. Capture the spider for later identification (crush the specimen, if necessary, but do so as gently as possible).

Black Widow Spider, The northern widow spider is infrequently found in the Upper Midwest. This species is one of the three closely related "black widows." Black widow spiders are shy and prefer secluded locations such as crawl spaces, attics, garages, and sheds where they construct a tangled, crisscross web. Common web locations are in stacked boards, firewood piles, in rubble, around water meters, under stones or other protected sites. Female northern widow spiders have round, shiny black abdomens, with two touching red triangles (the hour-glass marking) on the underside of the belly. They are up to ½ inch long. The female spends most of the day- light hours in a silken tunnel retreat and is helpless away from her web.

 Northern widow bites are often immediately painful. The most reliable evidence of a bite is two tiny red puncture marks around which the pain intensifies during the first three hours. The pain continues for 12-48 hours and then gradually subsides. "Black widow" venom contains a neurotoxin that can cause headache, dizziness, shortness of breath, and often painful abdominal spasms and back pain. Rigidity of limbs, increased blood pressure, and profuse sweating are other symptoms. Death seldom occurs in healthy adults though children and adults in poor health may die within 12-32 hours from asphyxia. Anyone suspecting a spider bite should receive medical attention as soon as possible. A commercial antidote is available for black widow spider bites.