Is the Hobo Spider Poisonous?

The hobo spider bites when they feel threatened.
The hobo spider bites when they feel threatened.

The hobo spider bites when they feel threatened. This species is frequently confused with other species of spiders, especially the brown recluse spider. The misinformation on hobo spiders is so prevalent that it was previously thought that they can produce necrotic lesions similar to that caused by brown recluse spiders.

At one point, these were thought to be poisonous like the brown recluse. However, the past 15 years of research evidence showed that such cases have been circumstantial and the hobo spiders are mostly harmless. Hobo spiders are not aggressive; however, they will bite when pressed against the skin. The poison released by a hobo spider bite is not strong enough to cause life-threatening complications, but there may be pain, headache, extreme nausea, fatigue in some people after being bitten.

What does the hobo spider look like?

The hobo spider has become established in at least six states in the United States. They displace many native spider species when they spread. Its name comes from its aggressive behavior following slight provocation. They tag along on rides with humans along major highways in the Pacific Northwest United States.

The spider is 40-50 mm in length. It is a brown-colored spider with dark or grey stripes along its body and solid light brown legs without any bands. It has an oblong belly with longer posterior spinnerets visible from above. Usually, the spider chooses to hide in dark places and moist areas, such as woodpiles, basements, retaining walls, large cracks, crevices or other cavities in rock walls, foundations, or other constructions. They often have a light stripe running down the middle of their bodies.

These spiders belong to the funnel-web spider family, and they hide in the funnel- or tube-shaped places. They can run quickly up to 3 feet per second from one place to another, and they are poor climbers.

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When to see a doctor?

Mostly these spiders are harmless. However, see a doctor, if any allergic reactions appear and there are symptoms beyond the bite, such as:

Apart from these symptoms, see a doctor if the bite is close to the eyes or if a child gets bitten.

Take the spider (if possible) to show it to the health care professional.

The following tips can help get rid of hobo spiders from the house:

  • Keep the house uncluttered.
  • Regularly dust and vacuum the house.
  • Sprinkle diatomaceous earth around the house and yard. The diatomaceous earth penetrates the shell-like cover of any insect and dries up their body, thereby killing them.
  • Use spider traps that are available commercially.
References
WebMD. Spider Bites: What You Need to Know. https://www.webmd.com/skin-problems-and-treatments/ss/slideshow-spider-bites

National Pest Management Association. Hobo Spiders. https://www.pestworld.org/pest-guide/spiders/hobo-spiders/

Rahmani F, Banan Khojasteh SM, Ebrahimi Bakhtavar H, Rahmani F, Shahsavari Nia K, Faridaalaee G. Poisonous Spiders: Bites, Symptoms, and Treatment; an Educational Review. Emerg (Tehran). 2014;2(2):54-58. ncbi.nlm.nih.gov/pmc/articles/PMC4614586/