There Malmignatta or Black Widow (Latrodectus tredecimguttatus) together with the Violin Spider (Red-bellied Loxosceles) is one of the two species of spiders present in Italy whose bite can cause symptoms of a certain medical importance. This spider is found in mainly dry, stony and arid areas for example between walls and rocks. The bite of the Black Widow is considered, in particular, a potential occupational risk for farmers and farm workers that can accidentally come across some specimens during the threshing of wheat or the harvesting of vegetables near the ground. The Malmignatta has a rather wide geographical distribution, in fact it is widespread throughout the Mediterranean basin, as well as in Ukraine, Russia, the Middle East, Central Asia and China, in areas with a hot-arid climate. It is undeniable that the two common names by which it is known in Italy instill a bit of fear; the name Malmignatta derives from malo (bad) and mignatta (leech), while the ominous name of Black Widow is due to the behavior of the females of these spiders that cannibalize the male immediately after mating.
What is Malmignatta like and where does it live?
The scientific name Latrodectus thirteenthguttatus (with thirteen drops) describes well a distinctive morphological character of this species, in fact both sexes have black, shiny legs and black body with 13 characteristic red spotsIn nature, double contrasting coloration, such as black and red or black and yellow, has a clear warning meaning for enemies and predators, and is an indicator of toxicity or an unpleasant taste.
There female of the Black Widow with a body that reaches dimensions also of 15mm it’s a lot bigger of the male which measures approximately 4 – 7 mm. It builds a very sparse and irregular web, apparently almost disordered among the blades of grass and chooses a den among the stones and clods of earth where it can lay the egg sacs with the fertilized eggs. The newborns emerge from the eggs 3 – 6 weeks after deposition.
The Malmignatta It is active from May to November and it is well adapted to arid and sunny environments; It hides among low vegetation, stones or cracks in the ground, between walls. Sometimes it finds refuge among agricultural tools especially if they are dirty with earth or in crevices and cracks where there is no humidity. As a consequence it’s hard to find it at home.
It is certainly not an attacking spider, but it can defend itself if disturbed or if you inadvertently approach its lair with a hand or a foot. After all, spiders have no interest in attacking humans, unlike many blood-sucking insects that must sting to get their blood meal. D
Danger of the Malmignatta bite
The entire genus Latrodectus to which the Malmignatta belongs, has species distributed throughout the world and much studied precisely because the bite has significant effects. The injected venom contains α-latrotoxina toxin capable of interfering with the membranes of nerve cells causing a reaction known precisely as Latrodectismcharacterized by cramps, muscle stiffness and significant allergic reactions.
Spider bite statistics are quite uncertain because it is difficult to detect in the Emergency Room the correlation between a lesion cutaneous and the species of spider that might have caused it; it should be possible to photograph or capture the specimen. Although there are no precise and updated statistics on the exact number of cases each year, it is estimated that bites are occasional and not frequentThis is because the Malmignatta is a shy, non-aggressive spider, and lives mainly in rural and rarely frequented areas, such as bushes, stony ground and uncultivated meadows.
So a spider bite is a rather serious event. rare. In any case, just to have some reference from the scientific literature, in the United States spider bites cause less than 3 deaths per year and from a study conducted in 2020 on spider bites of medical importance in the Mediterranean area it appears, for example, that in Switzerland they are esteemed every year an average of 55 bites per million inhabitants and only 2% of these have any medical interest and in Türkiye only have been reported 82 cases to the National Poison Control Center between 1995 and 2004 without fatal consequences.
What to do if you are bitten, symptoms and differences with the violin spider
Unlike the Violin Spider, The bite of the Black Widow is immediately painful and this pain intensifies as the hours pass and can last even 1 or 2 days. The bite itself causes severe muscle pain. Systemic symptoms are in most cases sweating, nausea, headache, fever and abdominal cramps, while local symptoms at the level of the bite generally involve swelling and redness of the affected area.
Reactions are possible allergic even a lot violent especially in subjects with fragilitybut death by spider bite is really rareso much so that in medical literature up to 2020 they only report two fatal cases due to bites Malmignattaone in the 2001 and one in the 2003.
From a study conducted by a group of researchers in Albania from 2009 to 2018, some interesting results emerged:
- The effects of the poison they seem to be more serious during the period summeryto high temperatureswhen the females after laying eggs become more aggressive and inject larger quantities Of poison;
- the poison generates complications serious also in function of the body mass of the patient, in fact it is particularly dangerous for children under 15 kg of weight;
- The toxicity of the venom and the quantity injected are related to several factors such as the seasonthe climate, the size of the female and her stage of development.
Precisely because of the habits of this spider, those who work in the fields and pick fruit or vegetables under the sun in summer are particularly exposed to its bite, especially at the level of hands and arms if not well protected. According to the MSD Manuals of Merck Sharp & Dohme Corp., in case of a bite from a Black Widow spider, a first aid cleaning the wound and applying ice on the part to reduce the pain; it is good to go as soon as possible in Ready Rescue for the necessary pharmacological treatments and for the administration of the antidote in the most serious cases. Very often, children, the elderly, heart patients or immunocompromised subjects require hospitalisation.
