Polk County Conservation

Brown Recluse Spiders

  • My neighbor was recently bitten by a brown recluse spider at a park. He ended up having surgery to remove some of the dead, infected tissue. Could there be recluse spiders living around my house? Are there any other poisonous spiders besides the brown recluse in Iowa?

    I hope your neighbor is doing well. All spiders are venomous. Their venom helps them kill or subdue their prey. Most spiders are harmless and won’t hurt humans. Iowans only have to be cautious around two spiders, the brown recluse and black widow spider. These two spiders can cause serious medical problems but is rarely fatal.

    Brown recluse spiders are found throughout the state in logs, mulch, outbuildings, and occasionally in dark areas of houses. Recluses are shy spiders that are not aggressive, but will bite if disturbed. These tiny spiders are only 1/4-3/8 inches long. A distinguishing characteristic of the brown recluse is the dark fiddle shaped area on the front half of its body.

    The black widow spider is not common in the state and is found in logs and woodpiles around homes. They are very shy and avoid light. Black widows range in size from 1/8-3/8 inches long. The female black widow is entirely black with a red hourglass shape on the underside of her abdomen. Male black widows do not bite and are often eaten by the female after mating.

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    Administration Office
    12130 NW 128th St
    Granger, IA 50109

    P: (515) 323-5300
    F: (515) 323-5354

    Monday – Friday, 8:00 a.m. – 4:30 p.m.

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