Summary: The Hobo Spider inhabits Central and Western Europe and was brought over to the Northwest United States in the 1930s. The Hobo spider spins funnel shaped webs and is known to come inside homes during the late summer or early fall. Its bite is venomous.
The Hobo spider is one of the most dangerous spiders living in the United States, after the Black Widow spider, and the Brown Recluse spider. The habitat of the Hobo spider includes Oregon, Washington, Idaho, Montana, Wyoming, Utah, and Colorado. It was brought to the United States sometime during the early 1930s, probably to a Seattle shipping port where egg cases were attached to wooden crates, which is a more likely scenario than live spiders making the journey from Europe.
The Hobo spider has a 1/3”-2/3” body size and is 2/3”-2” in size including the legs. Its body is brown and not very hairy. It has smooth, brown legs that are not striped or patterned. The male has golf-club shaped antennae on its head, which are actually the spider's sex organ. The spider has a herringbone pattern on the topside of its abdomen. It is nocturnal and lives in moderate climates with adequate moisture.
The Hobo is dangerous because it lives in places where it often comes into contact with humans, and because its bite can be very painful and have long lasting side effects. The Hobo spider bite is rarely, if ever, deadly. Sometimes the bite will not heal properly due to infection, or the dying off of cells from oxygen deprivation caused by the injected toxin. If skin cells die, also known as necrosis, then medical attention is needed. Other symptom from a Hobo bite might include headache, nausea, fatigue, temporary memory loss, super human strength, and vision impairment. Ok, just kidding about the super human strength part.
The Hobo's bite is often blamed on the Brown Recluse, but the Hobo bite does not usually have as severe effects as its Recluse counterpart. If you get a headache don't use aspirin because this may prolong the bleeding. Ice packs and heat packs should also not be used because they can cause increased tissue damage. Try to catch the spider that bit you and take it with you for identification if you feel that you need to go to the hospital.
Sometimes knowing the spider's gender and age will help determine how serious the effects of the bite will be. Don't scratch the bites, and observe them regularly and seek medical attention if signs of infection appear. Some rare complications from Hobo bites can be bone marrow failure and uncontrollable vomiting or diarrhea, which can result in death. This is very unlikely, but be aware that there is a risk of a condition that might need medical attention.
These spiders generally live outdoors under rocks or other debris, but many males will wander inside from the months of July to September. This is when they go off in search of a mate. The males will usually die after the mating season and their numbers decline significantly by the beginning of October.
Hobo spider's diet consists of cockroaches, houseflies, earwigs, silverfish, carpet beetles, and other pests that might be found indoors. The Hobos are not good climbers, so usually can be found at ground level. It builds a funnel shaped web that is also close to the ground. The wide opening of the web has trip wires strung above it used to trip up insects flying above the web causing them to fall into the web. The web is not sticky, so the Hobo spider usually stays in the narrow part of its web and waits for something to fall into it so it can quickly strike and feed.
It is difficult to prevent the spiders from entering a home when the house is in a heavily infested area. It might help to remove large stones or lawn ornaments that might provide the spiders with a hiding place. Wear gloves and long sleeved pants and shirts when turning over objects that might have spiders hiding under them. Many spider bites occur when the spiders are disturbed as a hand invades their privacy.
The Hobo spider is sometimes called the Aggressive House spider, but this name is inaccurate because the Hobos only attack when they feel threatened or they are biting to subdue food. The Aggressive House Spider label comes from a distortion of its scientific name which is Tegenaria agresti. This actually translates to “mat weaver of the field”, so don't believe the myths that the Hobo hunts down human victims to bite. The Hobos have very poor vision, so if one runs towards you rather than away from you, blame it on bad eyesight.
Try to secure spaces where the Hobo might make its way indoors. Seal up cracks in the foundation using a product like Xcluder and make sure there are no holes in screen doors or windows. You might also want to screen in drier vents. Pesticides are often unsuccessful at preventing Hobos from coming inside because pesticides are more likely to kill spider species that compete with or feed on the Hobo Spider. Orb Weavers, Cob Web spiders, and Jumping spiders have all been known to feed on the Hobo and these “good guys” might be killed by pesticides sprayed in the house, allowing the Hobo free range.
The Hobo Spider is probably the least well known of the three species of spider living in the United States that can be harmful to human health. The Black Widow and Brown Recluse might have a more severe bite than the Hobo, but the Hobo Spider identification characteristics should also be more widely recognized as the spider can be dangerous.
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