The western hobo spider was introduced to North America from Europe, by way of immigration and trade, and was first discovered in Pacific Northwest ports.
To this day, the western hobo spider is most commonly encountered in the Northwest, including Washington, Oregon, Idaho, northeastern Utah, Colorado, western Wyoming, and western Montana. The hobo spider has been identified in southern states, but is not known to inhabit the Southwest. However, the presence of the hobo spider seems to be extending into new areas rather quickly.
This spider received its “hobo” name because of its tendency to hitch rides with humans. This may include travelers or shipments of goods. The hobo spider is also known as the aggressive house spider.
Adult female hobo spiders are approximately half an inch in body length and males are slightly smaller. Both sexes have an elongated abdomen. Male hobo spiders wander throughout the summer seeking a female. Hobo spiders mate in the fall, and the female usually lays her eggs in September or October. Hobo spiders generally live for about two years.
Hobo spiders can be found in moist, dark areas such as crawl spaces or basements, and outdoors, under firewood piles, sheds, or rocks. They create funnel-shaped webs where they can hide and await prey.
The bite of a hobo spider is similar to that of a brown recluse in that it can cause necrotic (tissue destroying) wounds, but it is not fatal. A victim usually will notice a blister at the bite location, and other symptoms may appear 24 to 36 hours later. Symptoms include nausea, joint pain, headache, weakness or fatigue.
Bites from hobo spiders are often mistaken for brown recluse bites because of their similar symptoms. It is important for a bite victim to seek immediate medical care and take the spider along for identification, if possible.