The Hobo Spider (Tegenaria agrestis) is a member of the genus of spiders known as funnel web spiders.
The Hobo Spider is one of a small number of spiders in North America whose bites are generally considered to be medically significant.
Hobo Spider Characteristics
The female Hobo Spider reaches sizes of 11 – 15 millimetres. The male Hobo Spider measures 8 – 11 millimetres. There is no dimorphism (difference in form between individuals of different sex in the same species) in colour or markings. The Hobo Spiders colouration is rather subdued, being a mixture of brown and rust earth shades. Hobo Spiders have a herringbone pattern on the top side of their abdomens.
Although most Hobo Spiders have very hairy-looking legs, the legs of this spider are fairly smooth. Similar spiders have stripes on the legs and are often much larger. The Hobo Spider has solid light-brown coloured legs. Related species are quite similar in appearance and it requires technical training to identify them reliably.
Hobo Spider Habitat and Spider Webs
The Hobo Spider prefers moderately dry and warm environments, however, in Europe, it does not typically live in houses, largely due to competition from house spiders such as the Giant house spider (Tegenaria gigantea). The Hobo Spider is most commonly found in gardens, fields, hedges and similar places.
The Hobo Spider is quite rarely found in houses in Europe, where almost no envenoms have been reported and the harmless if similar-looking Barn funnel weaver spider (T. domestica) is far more common. Hobo spiders sometimes build their webs in or around human habitations.
The Hobo spider creates a non-sticky trip web that does not permanently stick insects to it. Instead, once the prey trips on the web the hobo spider attacks the prey before it can get away. This along with its poor eye site explains why they are noticeably more aggressive to humans then other spiders. Hobo Spiders have to attack to eat otherwise they would die of starvation. The webs they make are funnel shaped and are often attached to an object in the garden, by the foundation, between planters, or anything that remains stationary near the ground level. The Hobo spider also makes webs under homes and attach it to plants or weeds.
Hobo Spider Diet
Hobo spiders construct a funnel-shaped structure of silk sheeting and lie in wait at the small end of the funnel for prey insects to blunder onto their webs.
Hobo Spider Reproduction
The Hobo spider typically enters homes when it is in search of a mate. Male Hobo spiders tend to wander with this yearning around August time. He will generally be eaten after mating has been completed. The female Hobo spider produces several white to cream egg sacs, suspending them within her tangled web. The female Hobo spider can live for about two years, whereas the male will only live for a few months.
Hobo Spider Venom
Most bites from the Hobo spider occur when the spider is accidentally crushed or squeezed by a human. The spiders venom is strong enough to cause considerable local pain and has been reported to sometimes cause tissue death (necrosis) at and near the bite.
While the effects of Hobo spider bites can go so far as to include necrosis, they are not known to be fatal to healthy humans. The necrosis in the reported cases is similar to, however, less serious than the necrosis caused by the brown recluse spider. If such a lesion is severe it may take months to heal. Other reported symptoms include intense headaches that may last from a couple of days to a week and in some cases there were vision abnormalities or a general feeling of malaise (a feeling of general discomfort or uneasiness).
If a hobo spider is tending an egg sac, it may become aggressive if it perceives the egg sac to be threatened. However, they generally do not bite unless forced to protect themselves and in the majority of cases the hobo spider does not actually inject venom when it does bite.