Theridiidae  Sundevall, 1833 / Latrodectus  Walckenaer, 1805   7 species

Latrodectus geometricus  C. L. Koch, 1841

Description
Male

Palp similar to that of L. tredecimguttatus. Prosoma 2.4 mm long. Colouration as in female, but with more contrast.

Body length male: 3.4-6.2 mm
Female

Vulva: copulatory ducts forming 4 coils, spermathecae parallel. Prosoma brown, 4.4 mm long. Legs: patella and tip of tibia darker. Opisthosoma dark brown to black, dorsally with loop-like brown blotches, ventrally with a dark red marking. Opisthosoma clothed with very long hair-like bristles.

Body length female: 8.1-13 mm
Additional information

Usually around houses, under or between stones, or on low vegetations. Altitude up to 1050 m.

This species is assumed to be less toxic than the European L. tredecimguttatus, but it can bite humans, as also all other Latrodectus species in the world. Often, a bite causes significant effects, with severe and long-lasting pain in two-thirds of cases, preventing patients from sleeping in one-third of cases. Pain increases in more than half of the cases within the first hour and mostly radiates into the limbs or abdominal pain develops. Typical symptoms include sweating in about 70% of cases and further systemic effects in 20–30% of cases (nausea and vomiting in less than 20%, raised temperature and neuromuscular effects in about 10%, hypertension in less than 10% of cases). Pain usually lasts 1–2 days and the other symptoms 1–4 days. If needed, a symptomatic medical treatment is recommended.

This species of African origin is not native to Europe (alien species). Introductions to several countries did not lead to established populations but it occurs in Turkey.

Distribution
  Presence
  Not established
  No data
Global distribution (WSC 2017): Africa. Introduced to both Americas, Poland, Near East, Pakistan, India, Thailand, Japan, Papua New Guinea, Australia, Hawaii
Phenology
JanFebMarAprMayJunJulAugSepOctNovDec
 male  female
Females with egg sac in July.
Figures
References

Bayram A, Kunt K B, Danişman T (2017) The checklist of the spiders of Turkey. Version 2017 [last updated 11 January 2017], online at http://www.spidersofturkey.info

Helsdingen P J van (2010a) Araneae. In: Fauna Europaea Database (Version 2010.1), online at www.european-arachnology.org

Knoflach B, van Harten A (2002) The genus Latrodectus (Araneae: Theridiidae) from mainland Yemen, the Socotra Archipelago and adjacent countries. Fauna of Arabia 19: 321-361

Le Peru B (2011) The spiders of Europe, a synthesis of data: Volume 1 Atypidae to Theridiidae. Mém Soc Linn Lyon 2: 1-522

Levy G (1998c) Araneae: Theridiidae. In Fauna Palaestina, Arachnida III. Israel Academy of Sciences and Humanities, Jerusalem.

Nolan M (2012b) A button in a balafon; an occurrence of the widow spider Latrodectus geometricus C. L. Koch (Araneae, Theridiidae) in Ireland. Newsl Br arachnol Soc 124: 6-7

Rozwałka R, Dawidowicz Ł, Wawer W (2017b) Three alien spider species (Araneae: Theridiidae) newly found in Poland. Fragmenta Faunistica 60: 61-66

World Spider Catalog (2017) World Spider Catalog, version 18.5. Natural History Museum Bern, online at http://wsc.nmbe.ch, accessed on 5.10.2017. doi: 10.24436/2

Updates
21-11-2017 Image insert
18-11-2017 Distribution update Old value
04-06-2013 Image insert