Poisonous Creatures of the Mediterranean
by Vejay K Singh aka Dr Venom
www.DrVenom.org

Dangerous Spiders: The Black Widow

A close relative of the deadly Red Back Spider of Australia Latrodectus hasselti, the Mediterranean Black Widow Latrodectus tredecimguttatus (Rossi, 1790) is just as notorious. Known as the ‘Viuda Negra’ in Spanish, the female is easily recognised; a glossy black spider with pea sized abdomen, usually with red bars or spots and a leg span of around 25mm. The male is slightly smaller.

Widow spiders are mainly nocturnal, spinning sticky tangle webs in which to catch their prey. Once caught, the widow injects lethal venom that quickly kills its victim before eating it. They usually prey upon insects like crickets, but are able to overpower larger prey such as scorpions by wrapping them in gummy silk.

Latrodectus tredecimguttatus is considered the most dangerous spider in Europe. Other species of Latrodectus to occur in the Mediterranean region include Latrodectus hystrix, Latrodectus lilianae, the White Widow Latrodectus pallidus and the Brown Widow Latrodectus geometricus which are not as venomous.

Region  Widespread throughout the Mediterranean region; the typical spotted form is present on Corsica

Habitat  Dry arid areas such as scrubland and garrigue habitat         

Symptoms  Envenomation is followed by excruciating pain known as ‘Latrodectism’. The neurotoxic venom quickly attacks the nervous system. Symptoms can include headache, nausea, sweating, fever, temporary blindness, vomiting, abdominal cramps, hypertension, paresthesia, asphyxiation, tachycardia and respiratory failure which can in extreme cases lead to death.

First Aid    Most victims are usually bitten on their hands or arms; these should be kept below the heart level and the patient be immobilised until help arrives. Medical attention should be sought immediately. It is important that doctors are advised of the identity of the spider using this field guide. The severity of the condition will depend on the amount of poison inoculated and the health of the victim. Sometimes very little or no venom is injected resulting in a ‘dry bite’ although some victims may require treatment for shock.

Treatment may include the use of painkillers and muscle relaxants. The general treatment for serious cases is an intravenous dose of 10% calcium gluconate solution, magnesium sulphate and diazepam. The antivenin for Latrodectus is no longer produced in Europe due to the lack of demand and costly production process.

The False Black Widow Steoda paykullianus (above) resemble the more venomous Black Widows. They similar in size, glossy black with either a red, white, yellow or orange band at the front of the abdomen. The similar looking S grossa is uniform black, whilst S bipunctata is glossy brown with variable white markings. The False Widow Spiders (Steoda) are mildly venomous to humans.

SPIDER FACT FILE

ARACHNOPHOBIA is the fear of spiders, and is the most common phobia among humans; 1 in 3 people affected!

Arachnology is the study of spiders and arachnids, those who study spiders and related animals are called Arachnologists.

There are over 35,000 known species of spiders and an estimated 35,000 yet to be identified.

Only a small number of spiders are actually Dangerous;       even venomous species rarely bite people.

Cars are statistically more dangerous than spiders!

Spiders are very beneficial to our eco-systems, as they prey upon disease carrying insects and household pests.

Spider silk is the strongest natural fibre known to science, over six times stronger than steel!  

Read all about the Poisonous Creatures of the Mediterranean - Bites, Treatments & Identification. Available from all leading book stores and online. All Poisonous and Medically significant species of spiders, insects, reptiles, amphibians, centipedes and marine animals of the Mediterranean & Europe.

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