Aggressive House Spiders
Native to Europe, the aggressive house spider, or western hobo spider, was accidentally introduced to the Northwestern United States in the 1980s. They are found primarily in Washington, Oregon, Wyoming, Colorado, Utah and Montana.
The spider generated a considerable amount of concern when it was reported that venom might cause necrotic lesions similar to a brown recluse spider. However, subsequent research and a thorough evaluation of the literature have revealed that this is not the case. The spider is no longer considered to be a significant medical threat to the average person. Unfortunately, continued media and public misinformation perpetuates the contrary.
Hobo spiders typically produce funnel-shaped webs along areas such as stacks of bricks or landscaping timbers. The webs are seemingly flat, horizontal layers of silk threads that form a funnel-like abode at one end. When potential prey makes contact with the aggressive house spider’s web, the silk strands vibrate. Aggressive house spiders then emerge from the narrow end of their webs to consume the prey. If hobo spiders enter homes it may be through gaps in foundations as well as through doors and windows.
Like most spiders, hobo spiders are unwelcome indoor visitors. If you are experiencing spiders indoors, contact a local pest management professional.