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Species Eratigena atrica - Giant House Spider

Greater European House Spider - Eratigena atrica - female Giant Spider~! - Eratigena atrica Long-legged spider - Eratigena atrica - male Spider - Eratigena atrica - male Possible Tegenaria? - Eratigena atrica Hobo spider? - Eratigena atrica Adult female - Eratigena atrica - female Eratigena atrica or ... ? - Eratigena atrica
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Chelicerata (Chelicerates)
Class Arachnida (Arachnids)
Order Araneae (Spiders)
Infraorder Araneomorphae (True Spiders)
No Taxon (Entelegynes )
Family Agelenidae (Funnel Weavers)
Genus Eratigena
Species atrica (Giant House Spider)
Other Common Names
Greater European House Spider
Synonyms and other taxonomic changes
Previously genus Tegenaria (transferred to Eratigena in August 2013). (1)
Tegenaria duellica (= T. gigantea) & T. saeva were all synonymized with T. atrica (now Eratigena atrica) in that same paper.
Explanation of Names
C.L. Koch, 1843
Size
All measurements are for only the body, and do not include the legs.
Females: approximately 16-18 mm.
Males: smaller, approximately 10-12 mm.
Identification
No banding on the legs, but proportionally longer legs than its relatives Eratigena agrestis and Tegenaria domestica.
Range
Main population located in BC, OR, & WA.(2) Also collected from isolated populations in AB, SK, QC, NS, NF.(3) Please note that in 2013, three species were synonymized (duellica, saeva, & atrica), so many of the populations in eastern Canada were of what was (then) considered a separate species.

Habitat
In comparing the ranges of E. atrica and E. agrestis, E. atrica is more common in coastal locations and E. agrestis dominating the interior. Anecdotal evidence suggests that, where the two species are sympatric, E. atrica “out-competes” E. agrestis although the nature of their relationship is unclear. (Link #2, See Internet Reference section below.)

In an unpublished study (1980s) by Rod Crawford, Curator of Arachnids at the Burke Museum, E. atrica was found to outnumber E. agrestis by about 50 to 1 in Seattle-area house properties that had been occupied largely by E. agrestis 20 years before.

"Natural" populations found on cliff faces and rocky areas. ~ Rod Crawford

When found around human structures, it is often located in darker areas, such as flower beds, wood piles, and areas where it can weave a funnel-web. When it is found in homes, it often is found in the darker recesses of the basement, such as corners. It is a nocturnal spider, so generally it is discovered when the lights are turned on and the spider darts for cover (and/or its web).
Food
Insects, possibly other spiders.
Life Cycle
Life cycle images:

Egg sacs


(spiderling, juvenile, molted skin, adult female & male)

Remarks
This spider (like its relatives T. domestica and E. agrestis) was imported from Europe into the ports of the Pacific Northwest. The first known N. American record was from Vancouver Island in 1929. It did not reach Seattle until 1960.

The greater European house spider (E. atrica) is not dangerous to people. Some people may be intimidated by their size as male legspans can reach 4 inches (100 mm). However, Rod Crawford has never known one to bite a human (though they certainly could if they tried); they are so docile he uses them as hands-on demonstrators for school children.

The Hobo Spider (E. agrestis) is often confused with this spider. If you are unsure of the exact species, just be mindful of this confusion, and use caution when dealing with the spider. (See E. agrestis for more information about the hobo spider).

The presence of giant house spiders is a deterrent to the establishment of hobo spiders indoors. It out-competes and displaces the hobo spider indoors and male giant house spiders often kill male hobo spiders (without necessarily eating them)!
Internet References
1) zoo.org: A good fact sheet about the Giant House Spider (Greater European House Spider)
2) Newsletter of the Entomological Society of British Columbia, Volume 22, Number 1 July 2002 (an article by Robb Bennett: Hyperbole and Hysteria on the Path to Enlightenment – a Review of Current Tegenaria Projects of Relevance to Canadian Arachnologists)
Works Cited
1.Phylogeny and taxonomy of European funnel-web spiders of the Tegenaria−Malthonica complex (Araneae: Agelenidae) based upon mor
Bolzern, Burckhardt, & Hänggi. 2013. Zoological Journal of the Linnean Society 168(4): 723-848.
2.Distribution of the Medically-implicated Hobo Spider (Araneae: Agelenidae) and a Benign Congener, Tegenaria duellica, in the Uni
Richard Vetter et al. 2003. Journal of Medical Entomology 40(2): 159-164.
3.Checklist of the spiders (Araneae) of Canada and Alaska
Paquin, Buckle, Duperre, & Dondale. 2010. Zootaxa 2461: 1–170.