Hobo Spiders Facts, Identification & Control
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, Montana and the Pacific Northwest United States. Hobo spiders belong to the Family Agelenidae, a group of spiders known for their funnel-like web construction. These arachnids spin horizontal layers of entangled silk threads that serve as nests, detection devices and traps for potential prey.
Tegenaria agrestis are known as hobo spiders and aggressive house spiders. Because of its common features and color, the hobo spider can easily be confused with other spiders. The hobo spider female measures between 11 to 14 mm in body length. Its brown legs are solidly colored and exhibit no markings. Females have slightly larger abdomens than males. The males have a swollen appendage that appears menacing, but is merely the hobo spider’s reproductive organs. Hobo spiders exhibit varying hues of brown. They resemble many other common spiders such as wolf spiders and, some people have mistaken them for the brown recluse spider. The best characteristics to identify a hobo spider are difficult to see with the naked eye.
Behavior, Diet & Habits
Hobo spiders feed on various insects and may also consume other spiders. Hobo spiders weave webs in the shape of funnels. Prey that comes into contact with the web triggers vibrations along the silken structure, alerting the hobo spider. After attacking prey, hobo spiders consume them within the narrow end of their funnel-shaped webs.
Hobo spider webs also serve as mating grounds. Females generally remain within the perimeter of their nests, while males move about in search of potential mating partners. Males cautiously approach their female counterparts, mating only after finding that the female is receptive, rather than hostile. Females remain in their nests after mating. Males will either die soon afterward or move on.
As with most spider species, female hobo spiders have larger abdomens and are larger than males. Females can grow in excess of 14 mm in length, while males are rarely longer than 11 mm. Due to their brown hue, hobo spiders might be confused with brown recluse spiders but they occur in very different parts of the country and also have a distinctly different appearance. Recluses have six eyes arranged in pairs but hobo spiders have eight eyes clustered together.
Signs of a Hobo Spider Infestation
Funnel-shaped webs and the spider are the signs of their presence.
Do They Bite?
These arachnids usually defend themselves only when provoked or threatened. Hobo spiders are extremely protective of their egg sacs and will bite if they perceive a threat to their young. Oftentimes, humans do not realize that they are encroaching upon a hobo spider. This often occurs when a spider is residing in dark areas.
An initial study of the hobo spider venom reported their venom to be a medical threat that would produce necrotic lesions. Subsequent research has dispelled this, and the spider is no longer considered a medically threatening spider.
As a species of house spider, hobo spiders are most commonly found in and around human dwellings and work spaces. They inhabit lesser-used and dark areas of such places, thriving best in humid conditions. Hobo spiders may also be found beneath rocks and among woodpiles outside.
Although the hobo spider is known as a formidable predator, it is also a food source for other predators. Many different animals may prey upon hobo spiders as they do on other spiders. Possible predators can include centipedes, birds, rodents and even ants.
Mud-dauber wasps also may hunt for hobo spiders. Mud-dauber wasps could catch hobo spiders and bring them back to their nests to feed to their young.