Watch For Spiders in Undisturbed Areas |
| Of the approximately 2,000 kinds of spiders in the United States, only a few have bites of medical importance. In Nebraska, the black widow and the brown recluse are the most common poisonous spiders. Other species that can be quite common in homes are the parson spider and sac spider; however, their bites are generally non-toxic although they may result in localized allergic reactions in some individuals. Although only a few spiders are toxic or cause allergic reactions, if one has been bitten, it can be important to save the spider for identification purposes. |
Adult female black widow spiders are shiny and jet-black, with a round abdomen and two small, connected red triangles on the underside forming the characteristic red hourglass. They are small spiders, about ½ inch long not including the legs. Adult females build an irregular, tangled web of coarse silk in undisturbed areas, and only the adult female spider is venomous. A black widow's bite, in severe cases, may cause elevated blood pressure, nausea, vomiting and difficulty in breathing. Medical treatment involves specific medications that reduce pain and muscle spasms.
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Brown recluse spiders are medium-sized, tannish-brown to dark-brown spiders, with long, thin legs. They have a fiddle-shaped mark on their back. Nebraska is on the northern-most range for brown recluse spiders. Symptoms of a brown recluse bite include fever, nausea, headache, and vomiting. A skin lesion begins to develop 4-6 hours after the bite occurs, and may require medical treatment to heal properly. Early diagnosis and treatment are essential to alleviate the pain and speed healing of ulcerated tissue.
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Most people are bitten by a spider when they disturb a spider's web or nest in an area that hasn't been cleaned for a long time. The most effective spider control involves habitat modification. Whether indoors or outdoors, most spiders prefer undisturbed places. Therefore, it is important to remove debris near buildings and clean outdoor areas especially porches, under eaves, and other likely breeding places. Clutter in garages, basements, closets and storage areas should also be removed.
Be sure to dust and vacuum frequently around windows, corners of rooms, shelves, under furniture, and behind mirrors and pictures. If you see sac spider capsules, remove them. It is a good idea to wear gloves when cleaning. Because most spiders enter houses through small cracks and crevices, sealing entry points with caulk will be the most permanent solution to spiders wandering inside in the late summer and early fall. A consistent presence of spiders may be a sign of insect infestation, because spiders cannot survive long without food. Reducing the number of insects will decrease spiders.
For more information about common spiders and their control, visit:
Brown Recluse Spiders in Nebraska
Curious About Spiders?
Spiders of Medical Importance
Wolf Spiders in Nebraska
SOURCE: Barb Ogg, Ph.D., extension educator, Lancaster County, NU/IANR |
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