Eratigena atrica (Giant House Spider)

About Eratigena atrica

Taxonomic Hierarchy

→ Kingdom: Animalia
→ Phylum: Arthropoda
→ Class: Arachnida
→ Order: Araneae
→ Family: Agelenidae
→ Genus: Eratigena
→ Species: Eratigena atrica

Common Name (Official / AAS)

Giant House Spider

Other Common Names

Funnel Weaver, Drain Spider, Greater European House Spider

Author

Author of species name: Carl Ludwig Koch. First year published: 1843, as Tegenaria atrica.

Pronunciation

air-uh-TIH-gen-uh ah-TRISH-uh

Meaning

Eratigena is an anagram of the genus name Tegenaria (Bolzern et al. 2013). The specific epithet, atrica, is formed from atri– after the Latin noun for “atrium” with the addition of the –ica suffix meaning “belonging to” (often used when referring to habitats). So “from the house” or “from the hall” is our understanding of the name. This makes sense, as Koch mentions in his original (German) description of the species that he found it in a glass botanical house in Erlangen and that it also liked the warm spots on the interior of homes (Koch 1843).

Notable Previous Names

Previous names/synonyms of this species include Tegenaria gigantea, Tegenaria duellicaTegenaria saeva, and Tegenaria atrica. The current name, Eratigena atrica, was published by Bolzern et al. 2013.

Identifying Traits of Eratigena atrica

Size

Body length (excluding legs) of adult female ranges from 11-18 mm; adult males range from 10-18 mm. Some of the largest specimens can have up to a 4 inch leg span!

Female Primary Colors

Male Primary Colors

Eye diagram of Eratigena atrica

Eyes

Total of eight eyes. When viewed from the front, two horizontal rows of four; both rows (anterior and posterior) are slightly procurved, meaning they are arched upwards. Eyes are all round and roughly the same size.

Legs

Very long and of medium thickness (very, very long in adult males); same color as carapace and without any banding or markings whatsoever. Upon close inspection, thick black spines/hairs are present. Tip of each leg has 3 claws (these are called “tarsal claws”).

Body

Overall a brown color, with darker brown or black patterning. Male and female look the same, except for differences in size (plus, the male has enlarged palps, while the female doesn’t). The carapace is pyriform (pear-shaped) and is colored the same as the legs, a light brown color, and has two diffuse, longitudinal dark stripes on it. The dark stripes are usually broken up into pieces that almost resemble the blue portions of a Union Jack flag. Abdomen is oval-shaped and mottled with various shades of brown and gray; there is a conspicuous “herringbone” pattern on the top side that runs the full length. This pattern is a series of pale ‘V’ or triangle-shaped markings. Turning the spider over, you should see that the sternum (underside of the cephalothorax) has a solid, pale stripe running down the center of it, as well as six pale circles on each side. The sternum pattern is helpful for telling the difference between this species and the “hobo spider.”

Range of Eratigena atrica

Eratigena atrica can be found in the following states, provinces and territories across the United States and Canada. Our current understanding of each spider's distribution is drawn from numerous scientific publications and online spider submissions, in order to be as accurate as possible. It is important to remember that spiders do not adhere to the territorial lines decided on by humans, therefore these ranges are subject to change.

Important Range Notes

This species is native to Europe but was introduced to southern Vancouver Island, British Columbia in the early 20th century, and has since spread to mainland British Columbia as well as Washington and Oregon (Vetter 2003). There are records of this species being found in Alberta, Newfoundland & Labrador, Nova Scotia, Quebec, and Saskatchewan, but they were small, isolated populations (or single specimens that were accidentally transferred there). So please keep that in mind when viewing the range listing. The majority of this species’ established North American distribution is contained within British Columbia, Washington, and Oregon only.

United States

Canada

Additional Information

Habitat

The Giant House Spider is common in and around buildings in the western portions of Oregon, Washington, and British Columbia (other listed Canadian provinces had small, isolated populations). The webs can be found in dark corners of rooms, garages, sheds, under rocks and logs, etc. This species is often found inside bathtubs and sinks, having gotten stuck while trying to climb in for a drink of water.

Web

Constructs a web characteristic of most members of the family Agelenidae: a funnel-shaped retreat with a radiating flat sheet of webbing. Spider typically remains inside the retreat during the day, motionless, unless prey enters the web; at which point, it will then rush out to grab it. At night, the spider may stay perched out on the main sheet of webbing to await prey. It will dart back into the retreat if disturbed.

Season

Most specimens mature in the summer or fall and mate shortly thereafter.

Food

Prey is any insect or other spider that it is able to subdue. Because the spider is so fast on its web, and has powerful jaws for gripping its food, it can often take down prey much larger than itself.

Lifecycle

On warm nights in the summer and fall, the adult males wander in search of mates and may be caught scurrying across the floor when the lights are turned on. Females will typically construct more than one egg sac in their lifetime, and will suspend them in her web. If debris is available, the mother may attach some to the outside of the egg sac.

Remarks

Pictures of Eratigena atrica (Giant House Spider)

General

Female Spiders

Male Spiders

Filtering options are grayed out when we do not have pictures for the given perspective. If you are a spider photographer, you can submit pictures of spiders to help fill any voids in our ever expanding library.
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Lateral
  • City/Region: Aloha
  • State: Oregon
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Lateral, Webs
  • City/Region: Auvergne
  • Country: France
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Eyes
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Eyes
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Genitalia
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Genitalia
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Genitalia
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Norwich
  • Country: England
  • Eratigena atrica
  • Maturity: Immature
  • Attributes: Dorsal, Eyes, Spiderlings
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Lateral
  • City/Region: Suffolk
  • Country: England
  • Eratigena atrica
  • Maturity: Immature
  • Attributes: Dorsal, Spiderlings
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal, Eyes
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Attributes: Webs
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: FemaleFemale
  • Maturity: Immature
  • Attributes: Eyes, Webs
  • City/Region: Krain
  • State: Washington
  • Country: United States
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Eyes, Webs
  • Eratigena atrica
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Lateral
  • Country: England

References and Further Reading

Various Research Papers

Scientific Diagrams and Keys for Identification

References for the Casual Reader

Species guide last updated: May 30, 2016

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