# Eratigena atrica
**Eratigena atrica** (C. L. Koch, 1843) is a large funnel-web spider in the family [Agelenidae](https://www.edgepedia.org/agelenidae), known in English as the Giant House Spider and long familiar under its former name *Tegenaria atrica*. It is native to Europe and has been introduced to Canada and the United States, where it lives chiefly in and around buildings.[1](https://wsc.nmbe.ch/spec-data/7294) • [2](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0021199836)
| Key fact | Detail |
|---|---|
| Scientific name | *Eratigena atrica* (C. L. Koch, 1843); original combination *Tegenaria atrica*; synonyms include *Tegenaria nervosa* Simon, 1870 and *Tegenaria larva* Simon, 1875[1](https://wsc.nmbe.ch/spec-data/7294) • [3](https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=1121510) |
| Classification | Family Agelenidae; genus *Eratigena* Bolzern, Burckhardt & Hänggi, 2013, of which *E. atrica* is the type species[1](https://wsc.nmbe.ch/spec-data/7294) |
| Common name | Giant House Spider (accepted English name in the UK Species Dictionary)[2](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0021199836) |
| Distribution | Europe; introduced to Canada and the USA[1](https://wsc.nmbe.ch/spec-data/7294) |
| Habitat | Predominantly synanthropic, one of four house spiders among the European *Eratigena* and *Tegenaria*; listed as non-native in the UK[4](https://belgianspiders.be/wp-content/uploads/2023/12/J-Belg-Arachnol-Soc-38-2-2023.pdf) • [2](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0021199836) |
| Species status | The World Spider Catalog recognizes *E. atrica*, *E. duellica*, and *E. saeva* as three separate species after the 2018 revision by Oxford & Bolzern[5](https://araneae.nmbe.ch/data/241/Eratigena_atrica) |
| Genome | A male specimen's genome was assembled from 183.53 Gb of PacBio sequence (20.11 million reads)[6](https://pmc.ncbi.nlm.nih.gov/articles/PMC12553971/) |
## Taxonomy and nomenclature
C. L. Koch described the species in 1843 as *Tegenaria atrica*. Later names now treated as synonyms include *Philoica atrica* (Koch, 1850), *Tegenaria nervosa* Simon, 1870, *Tegenaria larva* Simon, 1875, and *Tegenaria hibernica* O. Pickard-Cambridge, 1892.[1](https://wsc.nmbe.ch/spec-data/7294) The Integrated Taxonomic Information System records the current standing as valid, with *Tegenaria atrica* and *Tegenaria nervosa* listed as synonyms, and sources its classification from the World Spider Catalog.[3](https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=1121510)
**The genus Eratigena.** In 2013, Angelo Bolzern of the Naturhistorisches Museum Basel, together with Daniel Burckhardt and Ambros Hänggi, revised the European funnel-web spiders of the ill-defined *Tegenaria*–*Malthonica* complex using morphological and molecular data. They redefined the two traditional genera and erected the new genus *Eratigena*, providing identification keys for the European agelenid genera and species; *E. atrica* became the type species of the new genus.[7](https://onlinelibrary.wiley.com/doi/abs/10.1111/zoj.12040) • [1](https://wsc.nmbe.ch/spec-data/7294) In the same revision, Bolzern and colleagues synonymized *E. duellica* and *E. saeva* under *E. atrica*, treating the giant house spiders as a single species.[5](https://araneae.nmbe.ch/data/241/Eratigena_atrica)
## One species or three
The synonymy did not last. Geoff Oxford of the [University of York](https://www.edgepedia.org/university-of-york) and Angelo Bolzern published a 2018 study titled "Molecules v. morphology — is *Eratigena atrica* (Araneae: Agelenidae) one species or three?", which revalidated *E. duellica* and *E. saeva*; the World Spider Catalog once again recognizes three separate species.[5](https://araneae.nmbe.ch/data/241/Eratigena_atrica) • [6](https://pmc.ncbi.nlm.nih.gov/articles/PMC12553971/) The three are visually indistinguishable in the field, and reliable identification to species requires examination of mature specimens, typically the male pedipalp or female epigyne.[8](https://srs.britishspiders.org.uk/resource/SRSNL105.pdf) The British Spider Recording Scheme notes that the concatenation of the three species into one defies the current evidence, and its guidance now covers all three species of the *Eratigena atrica* group with additional diagnostic characters.[8](https://srs.britishspiders.org.uk/resource/SRSNL105.pdf)
The group's evolutionary depth is old. [Molecular clock](https://www.edgepedia.org/molecular-clock) calibrations based on the mitochondrial CO1 gene suggest that deeper divisions within the genus *Tegenaria* may exceed 10 million years, and that the history of the *T. atrica* group has been shaped by [Quaternary](https://www.edgepedia.org/quaternary) glacial-interglacial cycles.[9](https://eprints.whiterose.ac.uk/id/eprint/273/)
## Distribution and synanthropic habitat
The World Spider Catalog gives the global distribution as Europe, with introductions to Canada and the USA.[1](https://wsc.nmbe.ch/spec-data/7294) In North America it occurs in the [Pacific Northwest](https://www.edgepedia.org/pacific-northwest); BugGuide records it from the states of Colorado, Idaho, Montana, Oregon, Utah, Washington, and Wyoming, and the Canadian provinces of Alberta and [British Columbia](https://www.edgepedia.org/british-columbia), with a recent accidental introduction in the Rouge River area of [Pickering, Ontario](https://www.edgepedia.org/pickering-ontario).[10](https://www.bugguide.net/node/view/1974) A review of introduced agelenids counts *E. atrica* among six large Palearctic agelenid species introduced to other continents.[11](https://library.sprep.org/sites/default/files/cabi-health-ias.pdf)
The species is strongly associated with human buildings. Four species of the genera *Eratigena* and *Tegenaria* can be considered house spiders because of their predominant synanthropic habitat choice, and *E. atrica* is one of them.[4](https://belgianspiders.be/wp-content/uploads/2023/12/J-Belg-Arachnol-Soc-38-2-2023.pdf) In the UK it is classified as non-native in the Natural History Museum's species dictionary.[2](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0021199836) In western Washington, Rod Crawford, curator of arachnids at the Burke Museum in Seattle, describes the species as a year-round indoor tenant that reaches sexual maturity in late summer and autumn, when males are noticed running through homes; he notes that the spiders are not dangerous and that indoor individuals cannot survive if moved outdoors.[12](https://www.axios.com/local/seattle/2023/09/21/mating-season-spiders-washington)
## Development and environmental requirements
Embryogenesis and post-embryogenesis in *E. atrica* depend on temperature and light. In a laboratory study, embryos, larvae, and the first two nymphal stages were incubated at constant temperatures of 12, 22, 25, and 32 °C under light, dark, and light/dark regimes. The extreme temperatures of 12 and 32 °C raised embryo mortality to 100 percent and significantly increased mortality of nymphs II, while larvae and nymphs I suffered reduced survival only at the lowest temperature. The lowest temperature also slowed development in all stages. Light effects were smaller and more variable: constant light reduced survival of nymphs I at lower temperatures but increased that of larvae, and it lengthened embryonic development and nymphal duration, particularly at 12 to 22 °C. The authors concluded that dark, warm sites around 25 °C give the fastest development and lowest mortality, which matches the species' preference for sheltered indoor locations.[13](https://www.sciencedirect.com/science/article/pii/S0306456517301262)
## Life history in the introduced range
In British Columbia, Canada, phenology and life-history data were collected for *E. atrica* and the co-occurring funnel weaver *E. agrestis* at two study sites, providing field data on the introduced Pacific Northwest populations.[14](https://www.cambridge.org/core/journals/canadian-entomologist/article/abs/lifehistory-data-for-the-funnel-weavers-eratigena-agrestis-and-eratigena-atrica-araneae-agelenidae-in-the-pacific-northwest-of-north-america/3521A4BE75D15D26906E5478114A95E2)
## Genomics
A chromosome-level genome assembly was produced from a male specimen as part of a genome sequencing program. [PacBio sequencing](https://www.edgepedia.org/pacbio-sequencing) generated 183.53 gigabases from 20.11 million reads, which were used to assemble the genome; the assembly resource is hosted by the University of York's Department of Biology.[6](https://pmc.ncbi.nlm.nih.gov/articles/PMC12553971/) The genome paper also reviews the species' taxonomic history, noting that the single-species suggestion was later refuted and that the World Spider Catalog again recognizes three separate species.[6](https://pmc.ncbi.nlm.nih.gov/articles/PMC12553971/)
## References
1. [World Spider Catalog: Eratigena atrica species page, Natural History Museum Bern](https://wsc.nmbe.ch/spec-data/7294)
2. [Natural History Museum Species Dictionary: Eratigena atrica](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0021199836)
3. [Integrated Taxonomic Information System Report: Eratigena atrica, TSN 1121510](https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=1121510)
4. [Journal of the Belgian Arachnological Society 38(2), 2023](https://belgianspiders.be/wp-content/uploads/2023/12/J-Belg-Arachnol-Soc-38-2-2023.pdf)
5. [araneae, Spiders of Europe: Eratigena atrica](https://araneae.nmbe.ch/data/241/Eratigena_atrica)
6. [The genome sequence of the house spider, Eratigena atrica (C.L.Koch, 1843) (Araneae: Agelenidae), PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC12553971/)
7. [Bolzern, Burckhardt & Hänggi (2013). Phylogeny and taxonomy of European funnel-web spiders of the Tegenaria–Malthonica complex. Zoological Journal of the Linnean Society 168: 723–848](https://onlinelibrary.wiley.com/doi/abs/10.1111/zoj.12040)
8. [Spider Recording Scheme News: the Eratigena atrica group](https://srs.britishspiders.org.uk/resource/SRSNL105.pdf)
9. [Mitochondrial differentiation, introgression and phylogeny of species in the Tegenaria atrica group, White Rose Research Online](https://eprints.whiterose.ac.uk/id/eprint/273/)
10. [BugGuide: Family Agelenidae, Funnel Weavers](https://www.bugguide.net/node/view/1974)
11. [Invasive Species and Human Health, CABI](https://library.sprep.org/sites/default/files/cabi-health-ias.pdf)
12. [Giant spiders are on the move in Seattle, Axios (21 September 2023)](https://www.axios.com/local/seattle/2023/09/21/mating-season-spiders-washington)
13. [The effect of temperature and light on embryogenesis and post-embryogenesis of the spider Eratigena atrica, Journal of Thermal Biology](https://www.sciencedirect.com/science/article/pii/S0306456517301262)
14. [Life-history data for the funnel weavers Eratigena agrestis and Eratigena atrica in the Pacific Northwest of North America, The Canadian Entomologist](https://www.cambridge.org/core/journals/canadian-entomologist/article/abs/lifehistory-data-for-the-funnel-weavers-eratigena-agrestis-and-eratigena-atrica-araneae-agelenidae-in-the-pacific-northwest-of-north-america/3521A4BE75D15D26906E5478114A95E2)
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*Topic: Encyclopedia › Life and health › Animals › Invertebrates › Arthropods › Arachnids › Spiders › Spider systematics and classification › Spider genera and species (araneomorph catalog) › Sheet-web and dwarf spider genera (Linyphiidae)*
*Initially written Sep 17, 2026 · Reviewed: Oct 21, 2026 · Edited: Oct 11, 2026; Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license