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Theridiidae Latrodectus

Latrodectus geometricus C.L. Koch, 1841

Brown Widow

Although the genus Latrodectus includes some highly venomous species such as the Black Widows in America and the Redbacks in Australia, the venom of L. geometricus is not as toxic as its other more notorious relatives.

The female is recognised by its banded legs, a pea-shaped abdomen, often with diagonal streaks, and a yellowish orange to reddish orange hourglass-shaped pattern on the venter. The patterns and background colour of the abdomen vary widely, as shown in the pictures on this page and the next.

Two adjoining egg sacs

Length♀ 7–10 mm; ♂ 3–6 mm
DistributionCosmopolitan, including Singapore, Malaysia (Johor, Penang, Selangor), Brunei, Philippines, Japan, Australia, Colombia.
HabitatNeglected corners of the house, particularly in garages, and sheltered recesses outdoor, such as eaves or window ledges.
BiologyThe irregular web is built near a corner with a retreat at the side and some silky scaffolding around it. Extending from the scaffolding are vertical or near vertical trapping threads attached to the bottom surface. These strong trapping threads, stubbed with glue droplets, ensnare crawling insects. In this species, the males show a behaviour of sexual sacrifice similar to that documented for the Australian Redback. During copulation, the male may suddenly somersault so that its rear abdomen reaches the mouthparts of the female. The female may then kill the male instantly and feed on it. Alternatively, it may wrap the male in silk without necessarily consuming it later. The egg sacs are spherical and spiky.

Taxonomy

Type Deposits*

  1. Holotype

    Museum für Naturkunde, Berlin (ZMB), Germany (database export of type material, March 2019); ♀ (2249)

  2. Holotype

    Museum für Naturkunde, Berlin (ZMB), Germany (database export of type material, March 2019); ♀ (2832) of Theridium zickzack

  3. Holotype

    Museo Zoologico di Storia Naturale "La Specola", Università degli Studi di Firenze (MZUF), Florence, Italy; ♀ (631) of Latrodectus geometricus subalbicans (Berdondini & Whitman, 2003)

  4. Holotype

    British Museum of Natural History (BMNH)/Natural History Museum (NHMUK), London, UK; Juvenile♀ of Chacoca distincta (Levi, 1959c)

  5. Syntype

    Museo Zoologico di Storia Naturale "La Specola", Università degli Studi di Firenze (MZUF), Florence, Italy; 1♀ (629) of Latrodectus geometricus modestus (Berdondini & Whitman, 2003)

  6. Syntype

    Museo Zoologico di Storia Naturale "La Specola", Università degli Studi di Firenze (MZUF), Florence, Italy; 1♀ 1 Juvenile (632) of Latrodectus geometricus obscuratus (Berdondini & Whitman, 2003)

  7. Syntype

    Oxford University Museum of Natural History (OUMNH) = Hope Entomological Collections Oxford (HECO), Oxford, UK; 1♂ 3♀ 1 Juvenile (1727-1728) of Latrodectus concinnus (Lotz, 1994a)

Taxonomic references*

  1. Latrodectus geometricus (Original description ♀)

    C. L. Koch, 1841a Die Arachniden: 117, f. 684 doi:10.5962/bhl.title.43744

  2. Latrodectus geometricus (♀)

    Thorell, 1875e On some spiders from New-Caledonia, Madagascar and Réunion: 138, pl. 25, f. 4

  3. Theridium zickzack (Original description ♀)

    Karsch, 1878b Über einige von Herrn JM Hildebrandt im Zanzibargebiete erbeutete Arachniden: 311, pl. 8, f. 1

  4. Latrodectus geometricus (♀, D♂)

    Keyserling, 1884a Die Spinnen Amerikas. Theridiidae. I. Hälfte: 148, pl. 7, f. 92 doi:10.5962/bhl.title.64832

  5. Latrodectus geometricus

    F. O. Pickard-Cambridge, 1902a Arachnida - Araneida and Opiliones: 378, pl

  6. Latrodectus geometricus (Synonym of Theridion zickzack)

    F. O. Pickard-Cambridge, 1902c On the spiders of the genus Latrodectus, Walckenaer: 252, pl. 27, f. 7

  7. Latrodectus concinnus (Original description ♂♀)

    O. Pickard-Cambridge, 1904b Descriptions of some new species and characters of three new genera, of Araneidea from South Africa: 152, pl. 10, f. 3-4

  8. Latrodectus geometricus (♀)

    Strand, 1908f Arachniden aus Madagaskar, gesammelt von Herrn Walter Kaudern: 464, f. B, D

  9. Latrodectus geometricus

    Carbonell, 1923a Algunos datos sobre las arañas del género Latrodectus que se hallan en la Argentina: 351, f

  10. Latrodectus geometricus (mf)

    Brazil & Vellard, 1926 Contribuição ao estudo do veneno das aranhas (continuação) (segunda memoria) Lycosa raptoria–Ctenus nigriventer–genero Latrodectus–genero Grammostola–Lasiodora curtior e Acanthoscuria sternalis: 266, pl. 22, 2 unnumbered figs.

  11. Latrodectus geometricus (♀)

    Petrunkevitch, 1930a The spiders of Porto Rico: 175, f. 14-16

  12. Chacoca distincta (Original description ♀)

    Badcock, 1932 Reports of an expedition to Paraguay and Brazil in 1926–7, supported by the Trustees of the Percy Sladen Memorial Fund and the Executive Committee of the Carnegie Trust for the Universities of Scotland: 11, f. 7 doi:10.1111/j.1096-3642.1932.tb00987.x

  13. Latrodectus geometricus (♂♀, Synonym of Latrodectus concinnus)

    Smithers, 1944 Contributions to our knowledge of the genus Latrodectus (Araneae) in South Africa: 301, f. 6c, 7b, 8d, 17-20

  14. Latrodectus geometricus obscuratus (Original description ♀)

    Caporiacco, 1949a Aracnidi della colonia del Kenya raccolti da Toschi e Meneghetti negli anni 1944-1946: 377

  15. Latrodectus geometricus (♂♀, Synonym of Latrodectus geometricus modestus, L. g. obscuratus and L. g. subalbicans)

    Levi, 1959c The spider genus Latrodectus (Araneae, Theridiidae): 21, f. 8-10, 25-28, 37, 39-51, 80-83 doi:10.2307/3223799

  16. Latrodectus geometricus (♀)

    Biasi, 1962 Estrutura interna e presença de segmentos do êmbolo no epígino de Latrodectus geometricus (Araneida: Theridiidae): 327, f. 1-2

  17. Latrodectus geometricus (♀)

    Levi & Levi, 1962 The genera of the spider family Theridiidae: 59, f. 253

  18. Latrodectus geometricus (♂♀)

    Abalos & Báez, 1963 On spermatic transmission in spiders: 198, f. 1-3, 20-22 doi:10.1155/1963/93732

  19. Latrodectus geometricus (♀)

    Chrysanthus, 1963 Spiders from south New Guinea V: 737, f. 53-54, 113

  20. Latrodectus geometricus (♂♀)

    Gerschman & Schiapelli, 1965c El género Latrodectus Walckenaer, 1805 (Araneae: Theridiidae) en la Argentina: 59, f. 10-11

  21. Latrodectus geometricus (♂♀)

    Abalos, 1967 La transferencia espermática en las arácnidos: 269, f. 11A-D

  22. Latrodectus geometricus (♂♀)

    Abalos & Báez, 1967a Las arañas del genero Latrodectus en Santiago del Estero: 24, f. 9-10, 15-16

  23. Latrodectus geometricus (♂♀)

    Abalos & Báez, 1967b The spider genus Latrodectus in Santiago del Estero, Argentina: 60, f. 4.11-12, 7-8

  24. Latrodectus geometricus (♂♀)

    Levi, 1967c Cosmopolitan and pantropical species of theridiid spiders (Araneae: Theridiidae): 185, f. 57-59

  25. Latrodectus geometricus (♀)

    Zumpt, 1968 Latrodectism in South Africa: 385, f. 2

  26. Latrodectus geometricus (♂♀, Synonym of Latrodectus distinctus, removed from Synonym of L. curacaviensis, rejecting Levi, 1959c: 39)

    Abalos, 1980 Las arañas del género Latrodectus en la Argentina: 49, f. 17, 65-68

  27. Latrodectus geometricus (♂♀)

    Levy & Amitai, 1983 Revision of the widow-spider genus Latrodectus (Araneae: Theridiidae) in Israel: 56, f. 42-46 doi:10.1111/j.1096-3642.1983.tb01720.x

  28. Latrodectus geometricus (♀)

    Müller, 1985a Abgebrochene Emboli in der Vulva der "Schwarzen Witwe" Latrodectus geometricus C: 27, f. 1-3

  29. Latrodectus geometricus (♀)

    Song & Qiu, 1987 On the classification of theridiid spiders (Araneida: Theridiidae): 82, f. 24 doi:10.15983/j.cnki.jsnu.1987.03.015

  30. Latrodectus geometricus (♂♀)

    Lotz, 1994a Revision of the genus Latrodectus (Araneae: Theridiidae) in Africa: 11, f. 1a-d, 2a, 2c-d, 8a

  31. Latrodectus geometricus (♂♀)

    Lotz, 1994b The button spiders of southern Africa (Latrodectus: Araneae: Theridiidae): 11, f. 1a-d, 2a, 2c-d, 8a

  32. Latrodectus geometricus (♀)

    Levy, 1998b Araneae: Theridiidae: 110, f. 203-206

  33. Latrodectus geometricus (♂♀)

    Knoflach & van Harten, 2002 The genus Latrodectus (Araneae: Theridiidae) from mainland Yemen, the Socotra Archipelago and adjacent countries: 339, f. 2, 20-28

  34. Latrodectus geometoricus (♂♀, lapsus)

    Yoshida, 2003a The spider family Theridiidae (Arachnida: Araneae) from Japan: 48, f. 97-102

  35. Latrodectus geometricus (♂)

    Knoflach & Pfaller, 2004 Kugelspinnen – eine Einführung (Araneae, Theridiidae): 138, f. 21a-b

  36. Latrodectus geometricus (♂♀)

    Agnarsson, 2004 Morphological phylogeny of cobweb spiders and their relatives (Araneae, Araneoidea, Theridiidae): 569, f. 54A-C, F, 55A-H doi:10.1111/j.1096-3642.2004.00120.x

  37. Latrodectus geometricus (♂)

    Agnarsson, Coddington & Knoflach, 2007 Morphology and evolution of cobweb spider male genitalia (Araneae, Theridiidae): 345, f. 12 doi:10.1636/SH-06-36.1

  38. Latrodectus geometricus (♀)

    Shukla & Broome, 2007 First report of the brown widow spider, Latrodectus geometricus C: 775, f. 1, 2a-c

  39. Latrodectus geometricus (♂♀)

    Bayram et al., 2008b A brown widow spider new for the Turkish araneo-fauna: Latrodectus geometricus C: 100, f. 2-3, 4a-d

  40. Latrodectus geometricus (♂♀)

    Yoshida, 2009b Uloboridae, Theridiidae, Ctenidae: 363, f. 74-77

  41. Latrodectus geometricus (♂♀)

    Saaristo, 2010 Araneae: 276, f. 37.154

  42. Latrodectus geometricus (♀)

    Le Peru, 2011 The spiders of Europe, a synthesis of data: Volume 1 Atypidae to Theridiidae: 455, f. 742

  43. Latrodectus geometricus (♂♀)

    Simó et al., 2013 Habitat, redescription and distribution of Latrodectus geometricus in Uruguay (Araneae: Theridiidae): 372, f. 1-2 doi:10.1590/s1676-06032013000100040

  44. Latrodectus geometricus (♂♀)

    Satam, 2015 Redescription of Latrodectus geometricus Koch, 1841 (Araneae: Therididae [sic]) with a new record of male from Mumbai (India): 37, f. 1-7

  45. Latrodectus geometricus (♂♀)

    Muslimin et al., 2015 First report of brown widow spider sightings in Peninsular Malaysia and notes on its globaldistribution: 1, f. 2A-E, G, I doi:10.1186/s40409-015-0010-2

  46. Latrodectus geometricus (♀)

    Rozwałka, Dawidowicz & Wawer, 2017 Three alien spider species (Araneae: Theridiidae) newly found in Poland: 62, f. 3-4 doi:10.3161/00159301FF2017.60.1.061

  47. Latrodectus geometricus (♀)

    Cazanove, 2019 Premier signalement de Latrodectus geometricus (Araneae, Theridiidae) sur l’île de La Réunion (Océan Indien) avec quelques notes sur son élevage: 11, f. 1A-B, 2, 3A-B, 4, 7A-B

  48. Latrodectus geometricus (♂♀)

    Wang & Zhang, 2019 [An invading "black widow" spider was discovered in China]: 124, f. 1, 2A-B, 3A-G doi:10.3969/j.issn.1005-9628.2019.02.009

  49. Latrodectus geometricus (♂♀)

    Sentenská et al., 2021 Functional morphology of immature mating in a widow spider: 3, f. 1a-c, 3a-b, 4a-b, 9a-d doi:10.1186/s12983-021-00404-1

  50. Latrodectus geometricus (♂♀)

    Cabrera-Espinosa & Valdez-Mondragón, 2021 Distribución y modelaje de nicho ecológico, comentarios biogeográficos y taxonómicos del género de arañas Latrodectus (Araneae: Theridiidae) de México: 4, f. 14-16, 18-20, 27-29, 38-41 doi:10.22201/ib.20078706e.2021.92.3665

  51. Latrodectus geometricus (♂♀)

    Dippenaar-Schoeman et al., 2021z The Theridiidae of South Africa. Part 1 A-P: 39, p. 37: 1 f., p. 39: 5 f., p. 40: 4 f., p. 41: 3 f. doi:10.5281/zenodo.7515890

  52. Latrodectus geometricus (♂♀)

    Abdel-Ghani, Hassan & Sallam, 2023 Spiders as a bio-agent factor in a mango greenhouse at Giza Governorate, Egypt: 37, f. 26a-b

  53. Latrodectus geometricus (♂♀)

    Baert et al., 2023 Updated checklist, origin, distribution, literature and genital drawings of the spiders of the Galápagos Islands: 32, f. 118A-D

  54. Latrodectus geometricus (♂♀)

    Murcia-Moreno & Gálvez, 2025 Introduced spiders in Panama: species distributions and new records: 7, f. 3A-D doi:10.3390/biology14010004

  55. Latrodectus geometricus (♂♀)

    Sentenská et al., 2025 Alternative mating tactics in brown widow spiders: mating with or without male self-sacrifice does not affect the copulatory mechanism: 4, f. 1a-b, 2a-f, 3a-d, 4a-e, 5a-b, 6a-i, 7a-c doi:10.1186/s12983-025-00560-8

  56. Latrodectus geometricus (♀)

    Sherwood, 2025b Annotated checklist of imported non-native spider (Araneae) taxa recorded in the United Kingdom 1800–2024: 147, f. 17A-C doi:10.15298/arthsel.34.1.10

* Retrieved from the World Spider Catalog.

Distribution Map for Latrodectus geometricus C.L. Koch, 1841

Cosmopolitan, including Singapore, Malaysia (Johor, Penang, Selangor), Brunei, Philippines, Japan, Australia, Colombia.

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