Examine individual changes

'{{Short description|Species of spider}} {{Unfocused|reason=the species has now been split into three again, so separate articles are needed|date=April 2020}} {{Speciesbox | name = Giant house spider | taxon = Eratigena atrica | image = Hausspinne Tegenaria atrica.jpg | image_upright = 0.9 | image_caption = | authority = ([[Carl Ludwig Koch|C. L. Koch]], 1843)<ref name=WSC_s670/> | range_map = Distribution.tegenaria.atrica.1.png | synonyms = {{Specieslist |Philoica atrica|(C. L. Koch, 1843) |Tegenaria atrica|C. L. Koch, 1843 |Tegenaria derouetae|Denis, 1959 |Tegenaria deroueti|Dresco, 1957 |Tegenaria duellica|Simon, 1875 |Tegenaria gigantea|Chamberlin & Ivie, 1935 |Tegenaria hibernica|O. Pickard-Cambridge, 1891 |Tegenaria larva|Simon, 1875 |Tegenaria nervosa|Simon, 1870 |Tegenaria praegrandis|Fox, 1937 |Tegenaria propinqua|Locket, 1975 |Tegenaria saeva|Blackwall, 1844 }} | synonyms_ref = <ref name=WSC_s670/> }} The '''giant house spider''' has been treated as either one species, under the name '''''Eratigena atrica''''', or as three species, ''E.&nbsp;atrica'', '''''[[Eratigena duellica|E. duellica]]''''' and '''''[[Eratigena saeva|E. saeva]]'''''. {{As of|2020|April}}, the three species view was accepted by the [[World Spider Catalog]]. They are among the largest spiders of [[Central Europe|Central]] and [[Northern Europe]]. They were previously placed in the genus ''[[Tegenaria]]''. In 2013, they were moved to the new genus ''[[Eratigena]]'' as the single species ''Eratigena atrica''.<ref name=Bolzern/> In 2018, the three separate species were restored.<ref name=Oxford2018/> The bite of these species does not pose a threat to humans or pets, and they are generally reluctant to bite, preferring instead to hide or escape. ==Description== The two sexes do not differ in coloration or markings. Its coloration is mainly dark brown. On its sternum is a lighter marking, with three light spots on each side that form an arrow-like shape pointing toward the head of the spider. The [[opisthosoma]] features a lighter middle line with six "spots" on each side. The giant house spider has the same coloration as the domestic house spider, ''[[Tegenaria domestica]]''; it has earthy tones of brown and muddy red or yellow. They also have conspicuously hairy legs, palps and abdomen. The female body size can reach {{convert|18.5|mm}} in length, with males having a slightly smaller body at around {{convert|12|to|15|mm}} in length. The female leg span is typically around {{convert|45|mm}}. The leg span of the male is highly variable, with spans between {{convert|25|and|75|mm}} being common.<ref name="usaspiders.com">{{Cite web|date=2021-02-06|title=Eratigena Atrica - Giant House Spider|url=https://usaspiders.com/eratigena-atrica-giant-house-spider/|access-date=2021-02-06|website=USA Spiders|language=en-US|archive-date=2021-02-21|archive-url=https://web.archive.org/web/20210221014103/https://usaspiders.com/eratigena-atrica-giant-house-spider/|url-status=live}}</ref> Its eight eyes are of equal size and are arranged in two rows. As the eyes contain fewer than 400 visual cells, ''E.&nbsp;atrica'' can probably only distinguish light and dark.{{citation needed|date=August 2022}} ==Taxonomy== The first description of a spider now assigned to this species was by [[Carl Ludwig Koch]] in 1843, under the name ''Tegenaria atrica''. Other supposedly different species were described later, including ''Tegenaria saeva'' by [[John Blackwall]] in 1844, ''Tegenaria duellica'' by [[Eugène Simon]] in 1875 and ''Tegenaria gigantea'' by [[Ralph Vary Chamberlin]] and [[Wilton Ivie]] in 1935. ''T.&nbsp;gigantea'' was [[Synonym (taxonomy)|synonymized]] with ''T.&nbsp;duellica'' in 1978. The three remaining taxa have been regarded as distinct species, particularly in Britain.<ref name=Bolzern/> Thus Roberts (1995) provides distinguishing characters for ''T.&nbsp;atrica'', ''T.&nbsp;duellica'' and ''T.&nbsp;saeva'',<ref name=Robe95>{{Cite book |last=Roberts |first=Michael J. |year=1995 |title=Spiders of Britain & Northern Europe |location=London |publisher=HarperCollins |isbn=978-0-00-219981-0 |pages=243–245}}</ref> as does Oxford (2008) for ''T.&nbsp;duellica'' (as ''T.&nbsp;gigantea'') and ''T.&nbsp;saeva''.<ref>{{cite journal |last=Oxford |first=G. |date=2008 |title=Identification of ''Tegenaria gigantea'' and ''T. saeva''|url=http://www.britishspiders.org.uk/srs/id/tegenaria.pdf |journal=Newsletter of the British Arachnological Society |volume=113 |pages=21–23 }}</ref> Others consider these three as part of a single morphologically variable species, for which the oldest name, and hence the senior synonym, is ''T.&nbsp;atrica''.<ref name=Bolzern/> A [[Phylogenetics|phylogenetic study]] in 2013 concluded that ''Tegenaria'', as then defined, was not [[Monophyly|monophyletic]], and split off some species, including ''T.&nbsp;atrica'', into the newly created segregate genus ''[[Eratigena]]''. The study also consolidated the various giant house spider species into one species, ''E. atrica''.<ref name=Bolzern/> A subsequent genetic study of ''E. atrica'' specimens determined that there were three distinct morphological groups, leading to the restoration of three separate species: ''E. atrica'', ''E. duellica'', and ''E. saeva''.<ref name=Oxford2018/> ==Distribution and habitat== ''E. atrica'' is found in [[Europe]], [[Central Asia]] and [[Northern Africa]]. It was unwittingly introduced to the [[Pacific Northwest]] of [[North America]] circa 1900 due to human activity and has strongly increased in numbers for the last century.<ref name=Vibertetal>{{Cite journal|last1=Vibert|first1=Samantha|last2=Salomon|first2=Maxence|last3=Scott|first3=Catherine|last4=Blackburn|first4=Gwylim S.|last5=Gries|first5=Gerhard|date=June 2017|title=Life-history data for the funnel weavers ''Eratigena agrestis'' and ''Eratigena atrica'' (Araneae: Agelenidae) in the Pacific Northwest of North America|url=https://www.cambridge.org/core/journals/canadian-entomologist/article/lifehistory-data-for-the-funnel-weavers-eratigena-agrestis-and-eratigena-atrica-araneae-agelenidae-in-the-pacific-northwest-of-north-america/3521A4BE75D15D26906E5478114A95E2|journal=The Canadian Entomologist|language=en|volume=149|issue=3|pages=345–356|doi=10.4039/tce.2016.73|s2cid=90621685|issn=0008-347X|access-date=2020-09-14|archive-date=2019-11-02|archive-url=https://web.archive.org/web/20191102071526/https://www.cambridge.org/core/journals/canadian-entomologist/article/lifehistory-data-for-the-funnel-weavers-eratigena-agrestis-and-eratigena-atrica-araneae-agelenidae-in-the-pacific-northwest-of-north-america/3521A4BE75D15D26906E5478114A95E2|url-status=live}}</ref> In the last few years{{when?|reason="the last few years" is uselessly relative and ambiguous; need specific time reference|date=November 2022}} the spider has been found in several European countries in which it was previously not recorded, like [[Estonia]], [[Latvia]] and [[Lithuania]]. It is recorded in the checklist of Danish spider species,<ref>Checklist of Danish Spiders (Araneae). Version 26-10-2011 ([http://www.zmuc.dk/EntoWeb/arachnology/dkchecklist.htm list] {{Webarchive|url=https://web.archive.org/web/20160304024828/http://www.zmuc.dk/EntoWeb/arachnology/dkchecklist.htm |date=2016-03-04 }})</ref> and is also found in [[Iceland]].<ref name=IINH/> The giant house spider's original habitat consists mostly of [[cave]]s, or dry forests where it is found under rocks, but it is a common spider in people's homes.<ref name="usaspiders.com"/> ==Biology and behavior== The [[spider web|webs]] built by the giant house spider are flat and messy with a funnel at one end. They do not contain sticky threads. The spider lurks in the funnel until a small invertebrate happens to get trapped in the web, at which point the spider runs out and attacks it. They usually build their webs in corners (on both the floor and ceiling), between boxes in basements, behind cupboards, in attics, or any other area that is rarely disturbed by large animals or humans. They are also often found near window openings.<ref name=Vibertetal /> ''E. atrica'' normally lives for two or three years, but lifetimes of up to six years have been observed. While the female only leaves its nest to feed, males can often be seen wandering around houses during the late summer and early autumn looking for a mate. Males can be found from July to October, adult females occur all year.<ref>{{Cite web|title=Summary for Tegenaria gigantea|url=http://srs.britishspiders.org.uk/portal.php/p/Summary/s/Tegenaria+gigantea|access-date=2020-09-10|website=srs.britishspiders.org.uk|archive-date=2017-10-05|archive-url=https://web.archive.org/web/20171005092029/http://srs.britishspiders.org.uk/portal.php/p/Summary/s/Tegenaria+gigantea|url-status=live}}</ref> At least 60 spiderlings emerge from an egg sac. Unusual for spiders, they are subsocial at this stage: they remain together for about a month, but do not cooperate in prey capture. The amount of cannibalism correlates with the amount of available food.<ref>{{cite journal |last1=Pourié |first1=Grégory |last2=Trabalon |first2=Marie |date=1999 |title=Relationships Among Food and Contact Signals in Experimental Group-Living Young of ''Tegenaria atrica'' |journal=Archives of Insect Biochemistry and Physiology |volume=42 |issue=3 |pages=188–197 |name-list-style=amp |doi= 10.1002/(SICI)1520-6327(199911)42:3<188::AID-ARCH3>3.0.CO;2-M |pmid=10536047 }}</ref> ''E. atrica'' molts seven or eight times before reaching the immature adult state, and after a final molt reaches maturity.<ref>{{cite journal |last1=Collatz |first1=K.G. |last2=Mommsen |first2=T. |date=1975 |title=Physiological conditions and variations of body constituents during the moulting of the spider ''Tegenaria atrica'' C.L. Koch (Agelenidae) |journal=Comparative Biochemistry and Physiology |volume=52 |issue=3 |pages=465–475 |doi= 10.1016/S0300-9629(75)80067-3 |pmid=241544 }}</ref> Like most spiders, the spider possesses venom to subdue its prey. Since ''E. atrica'' bites can penetrate human skin on occasion, the effects of [[agatoxin]] might be felt by bite victims, though these spiders will not bite unless provoked.<ref>{{Cite journal|last1=McKeown|first1=Nathanael|last2=Vetter|first2=Richard S.|last3=Hendrickson|first3=Robert G.|date=2014-06-15|title=Verified spider bites in Oregon (USA) with the intent to assess hobo spider venom toxicity|url=http://www.sciencedirect.com/science/article/pii/S0041010114000920|journal=Toxicon|language=en|volume=84|pages=51–55|doi=10.1016/j.toxicon.2014.03.009|pmid=24726469|issn=0041-0101|access-date=2020-09-10|archive-date=2021-12-10|archive-url=https://web.archive.org/web/20211210073853/https://www.sciencedirect.com/science/article/abs/pii/S0041010114000920|url-status=live}}</ref> With speeds clocked at {{convert|0.53|m/s|kph+mph+ft/s|abbr=on}}, the giant house spider held the [[Guinness Book of World Records]] for top spider speed until 1987 when it was displaced by [[Solifugae|solifugids]], although the latter are not true spiders.<ref>{{cite web |url=http://www.zoo.org/document.doc?id=203 |title=Giant House Spider (''Tegenaria gigantea'') |publisher=Woodland Park Zoo |access-date=20 August 2013 |archive-date=18 September 2013 |archive-url=https://web.archive.org/web/20130918063158/http://www.zoo.org/document.doc?id=203 |url-status=live }}</ref> ==Relationship with ''Eratigena agrestis''== A population of giant house spiders is popularly thought to be a deterrent to the establishment of ''[[Eratigena agrestis]]'', known in North America as the "hobo spider", and considered by some to be more likely to bite humans. Giant house spiders may compete with hobo spiders for the same resources. Hobo spiders grow no more than a body size of {{convert|15|mm|in}} long whereas the larger female giant house spider can have a body size of {{convert|18|mm|in}},<ref>{{cite web|url=http://bugguide.net/node/view/31446|title=Species ''Tegenaria agrestis'' - Hobo Spider|work=BugGuide|publisher=Iowa State University|access-date=20 August 2013|archive-date=9 September 2013|archive-url=https://web.archive.org/web/20130909100022/http://bugguide.net/node/view/31446|url-status=live}}</ref> but has proportionately much longer legs.<ref>{{cite web|url=http://bugguide.net/node/view/31449|title=Species ''Tegenaria gigantea'' - Giant House Spider|work=BugGuide|publisher=Iowa State University|access-date=20 August 2013|archive-date=27 September 2013|archive-url=https://web.archive.org/web/20130927103217/http://bugguide.net/node/view/31449|url-status=live}}</ref> ==In popular culture== Humorist [[David Sedaris]] has written about his relationship with ''E. atrica''. His essay "April in Paris" documents his growing affection toward and domestic association with giant house spiders, particularly one named April.<ref>{{cite magazine|url=http://www.newyorker.com/magazine/2008/03/24/april-paris|title=April & Paris|magazine=The New Yorker|date=17 March 2008|access-date=14 September 2014|archive-date=15 September 2014|archive-url=https://web.archive.org/web/20140915004314/http://www.newyorker.com/magazine/2008/03/24/april-paris|url-status=live}}</ref> The essay can be found in the collection ''[[When You Are Engulfed in Flames]]''. ==Gallery== <gallery mode="packed"> File:Tegenaria.atrica.creating.eggsac.1.jpg|Female constructing egg sac File:Tegenaria.atrica.spiderlings.on.egg.sac.jpg|Spiderlings File:Tegenaria duellica and dollar bill.JPG|''E. atrica'' can attain a leg span of up to {{convert|4|in|mm}}. This specimen is approximately {{convert|3|in|mm}} File:T duellica Moulting.jpeg|A [[molt]]ing ''E. atrica'' </gallery> ==References== {{Reflist|refs= <ref name=Bolzern>{{Cite journal |last1=Bolzern |first1=Angelo |last2=Burckhardt |first2=Daniel |last3=Hänggi |first3=Ambros |year=2013 |title=Phylogeny and taxonomy of European funnel-web spiders of the ''Tegenaria−Malthonica'' complex (Araneae: Agelenidae) based upon morphological and molecular data |journal=Zoological Journal of the Linnean Society |volume=168 |issue=4 |pages=723–848 |doi=10.1111/zoj.12040 |name-list-style=amp |doi-access=free }} {{free access}}</ref> <ref name=IINH>{{Cite web |title=Skemmukönguló (''Eratigena atrica'') |website=Náttúrufræðistofnun Íslands |publisher=Icelandic Institute of Natural History |url=http://www.ni.is/biota/animalia/arthropoda/chelicherata/arachnida/araneae/agelenidae/eratigena-atrica |access-date=2017-10-11 |language=is |archive-date=2017-10-11 |archive-url=https://web.archive.org/web/20171011232813/http://www.ni.is/biota/animalia/arthropoda/chelicherata/arachnida/araneae/agelenidae/eratigena-atrica |url-status=live }}</ref> <ref name=WSC_s670>{{cite web |title=Taxon details ''Eratigena atrica'' (C. L. Koch, 1843) |work=World Spider Catalog |publisher=Natural History Museum Bern |url=http://www.wsc.nmbe.ch/species/670 |access-date=2016-04-28 |archive-date=2016-06-04 |archive-url=https://web.archive.org/web/20160604032429/http://www.wsc.nmbe.ch/species/670 |url-status=live }}</ref> <ref name=Oxford2018>{{Cite journal | title = Molecules v. Morphology—is Eratigena atrica (Araneae: Agelenidae) One Species or Three? | date = 2018 | last1 = Oxford | first1 = Geoff S | last2 = Bolzern | first2 = Angelo | journal = Arachnology | volume = 17 | issue = 7 | pages = 337–357 | url = https://www.researchgate.net/publication/323752493 | doi = 10.13156/arac.2017.17.7.337 | s2cid = 90843479 | access-date = 2020-03-31 | archive-date = 2021-12-10 | archive-url = https://web.archive.org/web/20211210073903/https://www.researchgate.net/publication/323752493_Molecules_v_Morphology-is_Eratigena_atrica_Araneae_Agelenidae_One_Species_or_Three | url-status = live }}</ref> }}<ref>{{Cite web |last=DrfpLib |date=2019 |title=Eratigena atrica |url=https://drfp.online/index?/category/82-eratigena_atrica |url-status=live |website=DrfpLib}}</ref> ==Further reading== * {{cite journal |doi=10.1002/(SICI)1520-6327(1999)40:4<194::AID-ARCH4>3.0.CO;2-P|title=Contact sex signals on web and cuticle of ''Tegenaria'' atrica (Araneae, Agelenidae)|journal=Archives of Insect Biochemistry and Physiology|volume=40|issue=4|pages=194–202|year=1999|last1=Prouvost|first1=Olivier|last2=Trabalon|first2=Marie|last3=Papke|first3=Mirjam|last4=Schulz|first4=Stefan}} * {{cite journal |doi=10.1007/s00049-005-0308-6|title=Fatty acids mediate aggressive behavior in the spider Tegenaria atrica|journal=Chemoecology|volume=15|issue=3|pages=161–166|year=2005|last1=Pourié|first1=Grégory|last2=Ibarra|first2=Fernando|last3=Francke|first3=Wittko|last4=Trabalon|first4=Marie|s2cid=41683824}} ==External links== {{Commons}} * [https://www.youtube.com/watch?v=KQotdGRpgl8 Video of a feeding ''E. atrica''] {{Taxonbar|from=Q1071758}} [[Category:Agelenidae]] [[Category:Spiders of North America]] [[Category:Spiders of Europe]]'