Theridiidae  Sundevall, 1833 / Latrodectus  Walckenaer, 1805   8 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 2020): Africa. Introduced to both Americas, Poland, Middle East, Pakistan, India, Thailand, Japan, Papua New Guinea, Australia, Hawaii
Phenology
JanFebMarAprMayJunJulAugSepOctNovDec
 male  female
Females with egg sac in July.
Figures
Distribution List
Belgium   (no references) ||| Cyprus   (Bosmans et al., 2019c) ||| Egypt   (Bosmans, unpubl.) ||| Ireland   (Nolan, 2012b) ||| Libya   (Bosmans, unpubl.) ||| Morocco   (Bosmans, unpubl.) ||| Poland   (no references) ||| Turkey (Asia)   (Danışman et al., 2019) |||
References

Bosmans R, Van Keer J, Russell-Smith A, Hadjiconstantis M, Komnenov M, Bosselaers J, Huber S, McCowan D, Snazell R, Decae A, Zoumides C, Kielhorn K-H, Oger P (2019c) Spiders of Cyprus (Araneae). A catalogue of all currently known species from Cyprus. Newsletter of the Belgian Arachnological Society 34, Suppl. 1: 1-173 pdf

Bosmans R. (unpubl.) Provisional list of spiders of North Africa. Database excerpt Aug. 2019

Danışman T, Kunt K B, Özkütük R S (2019) The checklist of the spiders of Turkey. Version 2019 [last updated 1 June 2019], online at http://www.spidersofturkey.info pdf

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 pdf

Le Peru B (2011) The spiders of Europe, a synthesis of data: Volume 1 Atypidae to Theridiidae. Mémoires de la Société Linnéenne de Lyon 2: 1-522 pdf

Levy G (1998b) Araneae: Theridiidae. In Fauna Palaestina, Arachnida III. Israel Academy of Sciences and Humanities, Jerusalem. , 228 pp. pdf

Nolan M (2012b) A button in a balafon; an occurrence of the widow spider Latrodectus geometricus C. L. Koch (Araneae, Theridiidae) in Ireland. Newsletter of the British Arachnological Society 124: 6-7 pdf

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

World Spider Catalog (2020) World Spider Catalog. Version 21.0. Natural History Museum Bern, online at http://wsc.nmbe.ch (20.03.2020) doi: 10.24436/2 pdf

Updates
09-06-2020 Distribution update Detail
07-11-2019 Distribution update Detail
21-11-2017 Image insert
18-11-2017 Distribution update Detail
04-06-2013 Image insert