An Introduction to Hobo Spiders

Eratigena agrestis

Hobo spiders are funnel-web spiders from the spider family Agelenidae (they spin funnel-shaped or tube-shaped webs). They were previously known under the scientific name Tegenaria agrestis, but have recently been placed into a new genus, Eratigena (Bolzern et al.). You may know them as the "aggressive house spider", but the name is misleading as their behavior is not typically aggressive.

Two hobo spiders, female on left, male on right. Photograph. n.d. Eratigena agrestis (Hobo Spider). Spiders.us. Web. 4 April 2014.

Random fact: The "boxing gloves" seen on the male spider in the above image are his pedipalps. Pedipalps are a feature of all spiders, male and female. However, the male's are modified to store sperm, hence the enlargement of their ends.

Funnel web, spun by a giant house spider, Eratigena atrica. Photograph. n.d. Eratigena atrica (Giant House Spider). Spiders.us. Web. 4 April 2014.

The above photograph is an example of a funnel web. This particular one is from a giant house spider, Eratigena atrica. A hobo spider would spin a very similar web.

Distribution map of hobo spiders. Map. 2003. Distribution of the Medically-implicated Hobo Spider (Araneae: Agelenidae) and a Benign Congener, Tegenaria duellica, in the United States and Canada. Web.  17 February 2014.

Hobo spiders are found in the Pacific Northwest region of the United States (Washington, Oregon, Idaho, Montana, Wyoming, Colorado, and Utah). They are also found in southwestern Canada. They are an invasive species, native to Europe. There are also two closely related species which are also invasive in the same area: Eratigena atrica (giant house spider) and Tegenaria domestica (barn funnel weaver). These three different species are very similar in appearance and it is easy to misidentify them!

Female barn funnel weaver (left). Photograph. n.d. Tegeneria domestica (Barn Funnel Weaver). Spiders.us. Web. 4 April 2014.

Female giant house spider (right). Photograph. n.d. Eratigena atrica (Giant House Spider). Spiders.us. Web. 4 April 2014. 

Another random fact: Giant house spiders, Eratigena atrica, have previously been known under the scientific names of Tegenaria atrica, Tegenaria duellica, and Tegenaria gigantea. They were also renamed in the study by Bolzern et al.  

Hobo spiders have become notorious in the United States since Darwin Vest's publications in the late 1980's. His studies showed hobo spider bites caused some necrotic skin lesions in rabbits (Vest). These results were extended to humans, and the spiders quickly became infamous.