Steatoda

The spider genus ''Steatoda'', in the family Theridiidae, includes about 120 recognized species, distributed around the world (including many cosmopolitan species which are found among human populations worldwide). One common name is cupboard spider, for many species build their webs in dark, sheltered, undisturbed places around the house or garden, in sheds and garages, under garden, in compost bins, and cupboards. Signs of a ''Steatoda'' spider include a messy, tangled web with small white spots of spider droppings and insect exoskeletons in the area underneath the web.

Many spiders of the genus ''Steatoda'' are often mistaken for widow spiders (''Latrodectus''), and are known as false widows. The two genera are closely related – both occurring in the same family, Theridiidae – but ''Steatoda'' are significantly less harmful to humans. Not all ''Steatoda'' species resemble black widows – they come in many different colors and sizes, mostly smaller than ''Latrodectus'' species. '' Steatoda paykulliana'' can grow larger than the black widow, and '' Steatoda castanea'' looks more like a brown widow.

Description

The colour can range from sandy pale brown to reddish plum to satiny black. Like most spiders, its cephalothorax is smaller than its abdomen, which is somewhat egg-shaped, and can have white or beige to orange markings. Although sometimes not or partially visible, these markings usually consists of a frontal crescent, often with a dorsal line or triangular shapes or both. Orange to reddish-marked ''Steatoda paykulliana'' can be mistaken for the redback spider).

In common with other members of the family Theridiidae, ''Steatoda'' construct a tangled web, i.e., an irregular tangle of sticky silken fibers. These spiders have very poor eyesight and depend mostly on vibrations reaching them through their webs to orient themselves to prey or to warn them of larger animals that could injure or kill them.

File:Steatoda eye group.svg, The eye arrangement of spiders in the genus ''Steatoda''
File:Steatoda paykulliana 01.jpg, ''Steatoda paykulliana''
File:Steatoda nobilis.jpg, ''Steatoda nobilis''
File:Kaldari Steatoda grossa female 01.jpg, ''Steatoda grossa''
File:Steatoda castanea.JPG, ''Steatoda castanea''

Species

, the World Spider Catalog accepted the following extant species:

*'' Steatoda adumbrata'' (Simon, 1908) – Australia (Western Australia)
*'' Steatoda aethiopica'' (Simon, 1909) – Central Africa
*''Steatoda alamosa'' Gertsch, 1960 – US, Mexico
*'' Steatoda alboclathrata'' (Simon, 1897) – India
*''Steatoda albomaculata'' (De Geer, 1778) – North America, Europe, North Africa to Israel, Russia (Europe to Far East), Central Asia, China, Korea, Japan
*'' Steatoda anchorata'' (Holmberg, 1876) – Mexico to Chile
*''Steatoda ancora'' (Grube, 1861) – Russia (south Siberia)
*''Steatoda andina'' (Keyserling, 1884) – Venezuela to Chile
*''Steatoda apacheana'' Gertsch, 1960 – US
*''Steatoda atascadera'' Chamberlin & Ivie, 1942 – US
*''Steatoda atrocyanea'' (Simon, 1880) – New Caledonia, Loyalty Is.
*''Steatoda autumnalis'' (Banks, 1898) – Mexico
*''Steatoda badia'' (Roewer, 1961) – Senegal
*''Steatoda bertkaui'' (Thorell, 1881) – Indonesia (Moluccas), New Guinea
*''Steatoda bipunctata'' (Linnaeus, 1758) – Europe, Turkey, Caucasus, Russia (Europe to Far East), Iran, Central Asia, China. Introduced to South America
*''Steatoda borealis'' (Hentz, 1850) – US, Canada
*''Steatoda capensis'' Hann, 1990 – South Africa, Lesotho. Introduced to St. Helena, Australia, New Zealand
*'' Steatoda carbonaria'' (Simon, 1907) – Congo, Equatorial Guinea (Bioko)
*'' Steatoda caspia'' Ponomarev, 2007 – Kazakhstan
*'' Steatoda castanea'' (Clerck, 1757) (type species) – Europe, Turkey, Russia (Europe to Far East), Caucasus, Iran, Central Asia, China. Introduced to Canada
*'' Steatoda chinchipe'' Levi, 1962 – Ecuador, Peru
*'' Steatoda cingulata'' (Thorell, 1890) – China, India, Korea, Vietnam, Laos, Japan, Indonesia (Sumatra, Java)
*'' Steatoda connexa'' (O. Pickard-Cambridge, 1904) – South Africa
*'' Steatoda craniformis'' Zhu & Song, 1992 – China
*'' Steatoda dahli'' (Nosek, 1905) – Turkey, Israel, Caucasus, Russia (Europe) to Central Asia
*'' Steatoda diamantina'' Levi, 1962 – Brazil
*'' Steatoda distincta'' (Blackwall, 1859) – Madeira
*'' Steatoda ephippiata'' (Thorell, 1875) – Algeria to Israel, Iran
*'' Steatoda erigoniformis'' (O. Pickard-Cambridge, 1872) – East Mediterranean to Middle East, Caucasus, China, Korea, Japan. Introduced to the Caribbean.
*'' Steatoda fagei'' (Lawrence, 1964) – South Africa
*'' Steatoda fallax'' (Blackwall, 1865) – Cape Verde Is.
*'' Steatoda felina'' (Simon, 1907) – Congo
*'' Steatoda foravae'' Dippenaar-Schoeman & Müller, 1992 – South Africa
*'' Steatoda grandis'' Banks, 1901 – US
*'' Steatoda grossa'' (C. L. Koch, 1838) – Europe, Turkey, Caucasus, Russia (Europe to Far East), Central Asia, China, Korea, Japan. Introduced to North America, Ecuador, Peru, Chile, Hawaii Is., Macaronesia, Algeria, New Zealand
*'' Steatoda gui'' Zhu, 1998 – China
*'' Steatoda hespera'' Chamberlin & Ivie, 1933 – US, Canada
*'' Steatoda hui'' Zhu, 1998 – China
*'' Steatoda ifricola'' Lecigne, Lips, Moutaouakil & Oger, 2020 – Morocco
*'' Steatoda iheringi'' (Keyserling, 1886) – Brazil, Paraguay, Argentina
*'' Steatoda incomposita'' (Denis, 1957) – Portugal, Spain, France (incl. Corsica)
*'' Steatoda kiwuensis'' (Strand, 1913) – Central Africa
*'' Steatoda kuytunensis'' Zhu, 1998 – China
*''Steatoda latifasciata'' (Simon, 1873) – Canary Is. to Israel
*'' Steatoda lawrencei'' Brignoli, 1983 – South Africa
*'' Steatoda leonardi'' (Thorell, 1898) – Myanmar
*'' Steatoda lepida'' (O. Pickard-Cambridge, 1880) – New Zealand
*'' Steatoda linzhiensis'' Hu, 2001 – China
*'' Steatoda livens'' (Simon, 1894) – Australia (Tasmania)
*'' Steatoda longurio'' (Simon, 1909) – Central Africa
*'' Steatoda mainlingensis'' (Hu & Li, 1987) – Kyrgyzstan, China
*'' Steatoda mainlingoides'' Yin, Griswold, Bao & Xu, 2003 – China
*'' Steatoda marta'' Levi, 1962 – Colombia
*'' Steatoda maura'' (Simon, 1909) – Mediterranean
*'' Steatoda mexicana'' Levi, 1957 – US, Mexico
*'' Steatoda micans'' (Hogg, 1922) – Vietnam
*'' Steatoda minima'' (Denis, 1955) – Niger
*'' Steatoda moerens'' (Thorell, 1875) – Algeria, Tunisia
*'' Steatoda moesta'' (O. Pickard-Cambridge, 1896) – Mexico to Brazil
*'' Steatoda mormorata'' (Simon, 1910) – South Africa
*'' Steatoda morsitans'' (O. Pickard-Cambridge, 1885) – South Africa
*'' Steatoda nahuana'' Gertsch, 1960 – Mexico
*'' Steatoda nasata'' ( Chrysanthus, 1975) – Indonesia (Krakatau), Papua New Guinea (New Ireland), Australia
*'' Steatoda ngipina'' Barrion & Litsinger, 1995 – Philippines
*'' Steatoda nigrimaculata'' Zhang, Chen & Zhu, 2001 – China
*'' Steatoda nigrocincta'' O. Pickard-Cambridge, 1885 – China (Yarkand)
*''Steatoda niveosignata'' (Simon, 1908) – Australia (Western Australia)
*'' Steatoda nobilis'' (Thorell, 1875) – Macaronesia. Introduced to US, Chile, Europe, Turkey, Iran
*'' Steatoda octonotata'' (Simon, 1908) – Australia (Western Australia)
*'' Steatoda palomara'' Chamberlin & Ivie, 1935 – US
*'' Steatoda pardalia'' Yin, Griswold, Bao & Xu, 2003 – China
*'' Steatoda paykulliana'' (Walckenaer, 1806) – Europe, Mediterranean to Central Asia
*'' Steatoda pengyangensis'' Hu & Zhang, 2012 – China
*''Steatoda perakensis'' Simon, 1901 – Malaysia
*'' Steatoda perspicillata'' (Thorell, 1898) – Myanmar
*'' Steatoda picea'' (Thorell, 1899) – Cameroon
*'' Steatoda porteri'' (Simon, 1900) – Chile
*'' Steatoda punctulata'' (Marx, 1898) – US, Mexico
*'' Steatoda quadrimaculata'' (O. Pickard-Cambridge, 1896) – US to Venezuela, Caribbean
*'' Steatoda quaesita'' (O. Pickard-Cambridge, 1896) – Mexico
*'' Steatoda quinquenotata'' (Blackwall, 1865) – Cape Verde Is.
*'' Steatoda retorta'' González, 1987 – Argentina
*'' Steatoda rhombifera'' (Grube, 1861) – Russia (middle Siberia)
*''Steatoda rubrocalceolata'' (Simon, 1907) – Equatorial Guinea (Bioko)
*'' Steatoda rufoannulata'' (Simon, 1899) – India, Sri Lanka, Sumatra, Java
*'' Steatoda sabulosa'' (Tullgren, 1901) – Bolivia, Argentina, Chile
*'' Steatoda sagax'' (Blackwall, 1865) – Cape Verde Is.
*'' Steatoda saltensis'' Levi, 1957 – Mexico
*'' Steatoda seriata'' (Simon, 1899) – Indonesia (Sumatra)
*'' Steatoda singoides'' (Tullgren, 1910) – Tanzania
*'' Steatoda sordidata'' O. Pickard-Cambridge, 1885 – China (Yarkand)
*'' Steatoda speciosa'' (Thorell, 1898) – Myanmar
*'' Steatoda spina'' Gao & Li, 2014 – China
*'' Steatoda subannulata'' (Kulczyński, 1911) – New Guinea, Papua New Guinea (New Britain)
*'' Steatoda terastiosa'' Zhu, 1998 – China
*'' Steatoda terebrui'' Gao & Li, 2014 – China
*'' Steatoda tigrina'' (Tullgren, 1910) – Tanzania
*'' Steatoda tortoisea'' Yin, Griswold, Bao & Xu, 2003 – China
*'' Steatoda transversa'' (Banks, 1898) – US, Mexico
*'' Steatoda trianguloides'' Levy, 1991 – France (Corsica), Israel
*'' Steatoda triangulosa'' (Walckenaer, 1802) – Europe, Turkey, Caucasus, Russia (Europe to Far East), Central Asia. Introduced to Canada, US, Canary Is.
*'' Steatoda tristis'' (Tullgren, 1910) – Tanzania
*'' Steatoda truncata'' (Urquhart, 1888) – New Zealand
*'' Steatoda ulleungensis'' Paik, 1995 – Korea
*'' Steatoda uncata'' Zhang, Chen & Zhu, 2001 – China
*'' Steatoda variabilis'' (Berland, 1920) – East Africa
*'' Steatoda variata'' Gertsch, 1960 – US, Mexico
*'' Steatoda variipes'' (Keyserling, 1884) – Peru
*'' Steatoda vaulogeri'' (Simon, 1909) – Vietnam
*'' Steatoda venator'' (Audouin, 1826) – Libya, Egypt
*'' Steatoda wangi'' Zhu, 1998 – China
*'' Steatoda wanshou'' Yin, 2012 – China
*'' Steatoda washona'' Gertsch, 1960 – US, Mexico
*'' Steatoda xerophila'' Levy & Amitai, 1982 – Israel
*'' Steatoda xishuiensis'' Zhang, Chen & Zhu, 2001 – China

Those commonly mistaken for widows include:
* '' S. borealis''. A common species in North America, often mistaken for the black widow (despite being smaller and having colored markings on the dorsal side of the abdomen, rather than the ventral side).
* '' S. capensis'', the black cobweb or false katipo spider. It originates in South Africa, and is found in Australia and New Zealand; in the latter location it is often confused with the katipō spider.
* '' S. grossa'', often known as the cupboard spider. A dark-colored spider which resembles specimens of ''Latrodectus'', though without the characteristic red hourglass marks found on most widow spiders. Bites by ''S. grossa'' are rare but painful. Originally from Europe, but now found worldwide.
* '' S. nobilis''. This spider, a native of the Canary Islands, has since been introduced into the United Kingdom and across Europe. and sensationalized stories about the bite of ''Steatoda nobilis'' have featured in UK newspaper articles. Its bite is reported to be painful, but normally no worse than a wasp sting,
* '' S. paykulliana'', another spider which is often confused with ''Latrodectus''. This one is generally found in the range of ''Latrodectus tredecimguttatus'' and is frequently confused with it. Has a medically significant (but not serious) bite.

Other notable and recognizable species in the genus include:
* '' S. bipunctata''. A common house spider in Europe.
* '' S. triangulosa'', the triangulate cobweb spider, a common household spider noted for a pattern of triangles on the dorsal side of its abdomen. Not known to bite; found worldwide.
* '' S. hespera'', the western bud spider. This species is commonly found in the western United States and Canada, where it is an effective predator of the hobo spider. It is often confused with the black widow, despite being significantly smaller (7 to 8 mm) and having no bright-colored markings. Not known to bite humans, but has a venom which is similar to ''S. paykulliana'' (a medically significant spider of this genus).

Diet

''Steatoda'' is known to prey on other spiders (including true black widows), crickets, ladybugs, cockroaches, and woodlice.

Bites

Some members of this genus do have bites which are reported to have generalized symptoms in humans (such as '' S. grossa'' and '' S. nobilis''). However total number of cases are rare with one ever in France and England each, and 5 in Ireland. A review by Isbister noted 23 over 3 years in Australia. No bites require medical treatment. However, bites by ''Steatoda'' species generally do not have any long-lasting effects. Symptoms can include moderate to severe pain increasing for the first hour (without severe sweating). Some people have reported mild to moderate nausea, headache, and lethargy. The duration of all symptoms and effects can range from 1 to 60 hours.

The symptoms associated with the bite of several ''Steatoda'' species have been named steatodism; and have been described as a less-severe form of latrodectism (the symptoms associated with a widow spider bite). The redback spider antivenom has been thought to be effective at treating bites from ''S. grossa'', after it was mistakenly administered to a ''S. grossa'' bite victim who was erroneously believed to have been bitten by the far more dangerous redback. (While the redback antivenom appears clinically active against arachnidism caused by ''Steatoda'' spiders, ^{8 00 01 02/sup> as these cases are often mild and the evidence of its effectiveness is limited, this treatment is not recommended.) 0/sup>}

''Steatoda'' spiders are not aggressive, and most injuries to humans are due to defensive bites delivered when a spider is squeezed or pinched. It is possible that some bites result when a spider mistakes a finger thrust into its web for another arthropod, but intrusion by any large creature will cause these spiders to flee.

References

;General
*Levi, H.W. (1962). The Spider Genera ''Steatoda'' and ''Enoplognatha'' in America (Araneae, Theridiidae). '' Psyche'' 69:11-36
PDF
(with key to American species)

External links

Washington State University: ''Steatoda'' Spiders

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Theridiidae
Araneomorphae genera
Cosmopolitan spiders