Brown Recluse Spiders Make Appearance

By Robert J. Korpella

First posted on 08-17-2012

Two venomous spiders inhabit the Ozarks. One of them has sought shelter this summer by heading indoors. A number of people throughout the region reported seeing brown recluse spiders in greater numbers this year. Experts say that may be a result of a prolonged heat wave and drought that hit the Ozarks this summer.

With long, spindly legs and a slow, cautious gait, the brown recluse is just plain creepy. While sizes vary, the average recluse is about as large as a quarter when its legs are fully extended. Adult females are larger than males.

Body color varies from tan to a light gray with no banding on the legs or body. The abdomen may be light brown, gray or black depending on what the brown recluse ate that day. Nighttime hunters, these spiders forage for insects, and they’ll consume them either dead or alive.

While the distinctive violin-shaped marking on its back is a telltale indicator of a brown recluse, the more reliable identifier is in the eyes. Brown recluse spiders have 3 sets of 2 eyes each while most other spiders have 8 eyes. Of course, you’ve got to get pretty close to the specimen with a strong magnifier to make that identification.

Outdoors, the brown recluse lives under rocks, in debris, or in wood piles. They’ve adapted well to harsh weather environments and can live for months without food or water.

Those survival characteristics serve them well indoors, too. A brown recluse can live through icy winters in an unheated crawlspace or basement, and through scorching summers in attic spaces. During the daytime they like to hide in seldom-used, untidy drawers, cluttered garages or quiet corners.

They may wander into shoes, clothing or bedding while hunting at night, and that’s how most people get bitten. Brown recluse spiders are not aggressive and will not attack people. But, like any wild creature, they will defend themselves if they feel threatened.

Bites are rare, usually occurring when human body pressure frightens the spider, like when someone rolls over in bed and on top of the spider. The animal’s fangs are tiny and they cannot penetrate through clothing. About 90 percent of the time, a brown recluse bite gets sore, swells, reddens, sometimes hardens, then goes away in a few weeks.

However, bites can be serious for some people. Wounds sometimes blister, then develop a depression that scales and turns blue. Necrosis develops as the spider’s venom continues to attack the tissue. Physician diagnosis is difficult since the injured skin resembles other types of problems. Still, medical treatment is indicated since any open sore invites bacterial infection.

Brown recluse spiders aren’t nest builders that use webbing to trap food. They do make untidy looking webs for shelter and in which to enclose egg sacs. Females produce 40-50 eggs in a sac and they produce about 5 egg sacs in a lifetime. Most brown recluse spiders live for 2-4 years.

Adult females stick pretty close to their hideouts, seldom traveling any great distances. Males and juvenile spiders of either sex roam in search of a good meal.

A brown recluse infestation presents a challenge since these arachnids spend so much time in hiding. Flat, sticky traps made for trapping rodents are effective when placed at wall to floor junctions where spiders travel.

The University of Kentucky recommends “Bayer Advanced Multi-Insect Killer, Spectracide Triazicide, and Ortho Home Defense Max,” or home insecticides that have cypermethrin, cyfluthrin, bifenthrin, deltamethrin and lambda cyhalothrin as active ingredients. The best idea may be to contact a professional.

Be on the lookout for these spiders in your home, and use caution when going through seldom used spots in your house.