''Latrodectus tredecimguttatus'', also known as the Mediterranean black widow,
or the European black widow,
is a species in the genus ''
Latrodectus
''Latrodectus'' is a broadly distributed genus of spiders with several species that are commonly known as the true widows. This group is composed of those often loosely called black widow spiders, brown widow spiders, and similar spiders. Howeve ...
'' of the widow spiders. It is commonly found throughout the
Mediterranean region
In biogeography, the Mediterranean Basin (; also known as the Mediterranean Region or sometimes Mediterranea) is the region of lands around the Mediterranean Sea that have mostly a Mediterranean climate, with mild to cool, rainy winters and wa ...
, ranging from southern
Iberia
The Iberian Peninsula (),
**
* Aragonese and Occitan: ''Peninsula Iberica''
**
**
* french: Péninsule Ibérique
* mwl, Península Eibérica
* eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...
to southwest and central Asia, hence the name. Specimens from central Asia are also known by the binomial name ''Latrodectus lugubris''; that name, however, is now considered improper, though it is still commonly found in the literature. ''Latrodectus tredecimguttatus'' was previously considered a subspecies of ''
Latrodectus mactans
''Latrodectus mactans'', known as southern black widow or simply black widow, and the shoe-button spider, is a venomous species of spider in the genus ''Latrodectus''. The females are well known for their distinctive black and red coloring and f ...
''.
Description
![Population area of the Latrodectus tredecimguttatus](https://upload.wikimedia.org/wikipedia/commons/5/5b/Population_area_of_the_Latrodectus_tredecimguttatus.png)
''L. tredecimguttatus'' is black in color, similar to most other widow species, and is identified by the thirteen spots which are found on its dorsal abdomen (the species name is
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
for "with thirteen spots"). These spots are usually red in colour, but may also be yellow or orange. It is otherwise similar to other species in the genus ''Latrodectus''. The Mediterranean widow primarily lives in steppes and other grasslands, and can be a significant problem in areas where grain is harvested by hand. The female of the species has a body length of about , while the male is smaller and reaches at best. Only the female spider's bite is dangerous (either for humans or cattle) as the male cannot penetrate the relatively thick epidermis.
Toxicity
Like all ''Latrodectus'' species, ''L. tredecimguttatus'' has a painful bite that is fatal in rare cases. They are not in close association with humans generally, although epidemics of bites have been reported. There are many reports of Ukrainian farm workers receiving bites while working in the fields. The
LD-50
In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is th ...
of ''L. tredecimguttatus'' venom has been measured as 0.59 mg/kg, and separately again as 0.59 mg/kg (with a confidence interval of 0.33–1.06).
In
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
– where it has the common name ''karakurt'' (literally "black worm") – there are reports of this species biting and killing
camels. Pioneering
entomologist Jean Henri Fabre
Jean-Henri Casimir Fabre (21 December 1823 – 11 October 1915) was a French naturalist, entomologist, and author known for the lively style of his popular books on the lives of insects.
Biography
Fabre was born on 21 December 1823 in Saint ...
wrote of the spider's fearsome reputation in
Corsica, where it is known as the ''malmignatte'':
I have seen her settle in the furrows, lay out her web and rush boldly at insects larger than herself; I have admired her garb of black velvet speckled with carmine-red; above all, I have heard most disquieting stories told about her. Around Ajaccio and Bonifacio, her bite is reputed very dangerous, sometimes mortal. The countryman declares this for a fact and the doctor does not always dare deny it.[Fabre, Jean Henri, ''The Life of the Spider'' (transl. A.T. de Mattos), Ch.1, p.40 (New York 1917).]
/ref>
One crustacean-specific and two insect-specific neurotoxins have been recovered from ''L. tredecimguttatus'', as have small
peptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.
...
s that inhibit
angiotensin-1-converting enzyme.
References
External links
The World Spider Catalog* https://archive.today/20121220052505/http://www.srv.net/~dkv/hobospider/widows.html
* http://naturdata.com/Latrodectus-tredecimguttatus-13272.htm
{{Taxonbar, from=Q756200
tredecimguttatus
Spiders of Europe
Spiders of Asia
Spiders described in 1790
Taxa named by Pietro Rossi