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The prevalence of sexual cannibalism, in which the female eats the male after mating, influenced the species' common name, black widow . This species is considered to be one of the most poisonous. The venom of a female spider exceeds the toxicity of toxic substances in a rattlesnake. However, only a female bite is dangerous to humans. The bites of male and teenage spiders are harmless.
Does the black widow live in Russia?
In Russia, spiders from the genus Latrodectus live in warm regions, for example in the steppes of Kalmykia, the Astrakhan region, as well as in the Black Sea and Azov regions.
There were cases of bites in the Orenburg, Kurgan and Saratov regions. This summer (2019), many news headlines were full of reports of attacks by black widows in the Moscow region, and even cases of bites were recorded, but without deaths.
Since spiders can travel using their web as a sail and thus move over long distances, this explains their appearance in the Moscow region.
Here you need to understand that most likely one of the varieties of the black widow Latrodectus tredecimguttatus ended up in the Moscow region, and not the deadly spider Latrodectus mactans.
Latrodectus tredecimguttatus is the European black widow, or our usual name karakurt. This is also a dangerous spider, it has external similarities with the species Latrodectus mactans, but is still less toxic.
Karakurt (Latrodectus tredecimguttatus)The poison contains a lethal dose of dangerous neurotoxin LD 50
- Latrodectus tredecimguttatus - 0.59 mg/kg;
- Latrodectus mactans - 0.90 mg/kg.
That is, in terms of the toxicity of the poison, the Russian spider is almost two times less poisonous compared to the “real” Black Widow.
Karakurt (Latrodectus tredecimguttatus)
It is regularly found in Crimea, and very rarely it can even be found in the Moscow region.
The habitat of the “real” deadly black widow Latrodectus mactans is the hot regions of the United States.
The genus of spiders of the Black Widow family (Latrodectus) has more than 31 species, and among them there are spiders very similar to the real black widow, most of them are less toxic compared to the species Latrodectus mactans.
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Home maintenance
In pursuit of the exotic, many people forget about their safety and get a black widow spider as a pet. By and large, no special conditions are required to keep this arthropod creature: place it in a terrarium and don’t forget to feed it. If the spider escapes, then catching it even in a small apartment will be quite problematic. Also, you should not expect to be able to see the entire life cycle. They breed in captivity very rarely.
Black Widow Identification
The size and appearance of male and female spiders differ from each other. The female is larger, its size, excluding legs, ranges from 8 to 13 mm, and its weight averages about 1 gram.
Black widow, Latrodectus mactans, distinguished from other species by a red spot on the abdomen in the shape of an hourglass
An adult female has a more rounded and voluminous body compared to the male. The color is glossy black, with a red, hourglass-shaped spot on the belly that serves to warn off predators. Sometimes there may be a stripe consisting of irregular red spots appearing on the upper body.
The male's body is smaller, with the exception of the legs, measuring from 3 to 6 millimeters. The body is elongated, on the side of the abdomen there are 4 pairs of white and red stripes. Young males are mostly white, orange and brown. They become darker in color as they mature.
Spiders are arthropods. Protection of the body from small predators is provided, like all spiders, by a shell that constantly changes during the molting process. During molting, the spider is more vulnerable.
The spider has 8 eyes, which are arranged in two horizontal rows of 4. The pair of eyes in the center of the bottom row is considered primary, and the rest are considered secondary.
Life cycle
Spider with cocoons.
Mating occurs in spring and summer. The female is laying eggs. Usually it is 200 eggs. The females cover them with cobwebs, forming a protective sac. They hang it on a web to protect it from predators.
After 14 days, spiderlings appear. Several molts occur during the arachnid's maturation. Nutrition and temperature influence the formation of spiders.
Spiders mature within 2-4 months. The lifespan of females is from one to two years, and that of males is no more than 4 months. Many die before they reach full adulthood. Even representatives of the same offspring often eat each other when close to the mother.
Black Widow's Habitat
Although Latrodectus mactans is a very dangerous spider, it is a timid, shy, solitary and non-aggressive spider. It builds its lair in quiet places, making it difficult to find and detect. It is a nocturnal animal and spends most of its time during the day in a shelter or protected area.
Spiders of this species live in various secluded places.
Like all spiders, the widow spider is a carnivore, feeding on insects, but can attack and eat another spider, including those from its own genus. He traps his prey with a web and immobilizes him with the poison he injects, along with digestive enzymes. It can easily catch and kill even a bird or small animal.
The predator that preys on the black widow is California wasps in the United States. Scientific name Chalybion californicum.
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Black Widow bite and venom
As we wrote above, this spider is shy and timid, so it can bite only in self-defense or fright. When it bites, it injects only a small dose of venom, which can rarely kill a healthy person.
Those at risk of death from its bite are children, the elderly, or those with weakened immune systems.
In all cases, it is important to begin treatment immediately after the bite, since it is not known how the toxins from the poison will behave in the body.
A spider bite is practically painless and can go unnoticed right away, for this reason it is difficult to understand why the person felt ill.
Black widow venom contains the neurotoxin alpha-latrotoxin, as well as adenosine, guanosine and inosine. These substances cause muscle contractions, headaches, nausea, dizziness and severe abdominal pain. Sweating and difficulty breathing may occur.
The poison is strong, its lethal dose LD50 is 0.90 mg/kg.
Latrodectus mactans bite
Fortunately for humans and other animals, black widows are able to control the amount of poison injected into the victim. Depending on the situation, they may inject their venom, but in most cases this is not the case. The production of venom for a spider requires a lot of energy, and it does not need to bypass the venom in order to feed, so it tries not to waste it again.
The spider uses its bite in two cases: attack and defense. When attacking or defending offspring, the black widow injects a small amount of venom proportional to the size of the victim.
During defense, the spider bites only when it is necessary; it prefers to retreat and escape. Typically, when a black widow bites a person, the bites contain no or minimal venom.
Almost all bites of this spider occur due to the fact that a person stepped on it, or stuck their hand where it lives.
It happens that during the night a spider can build its shelter in a person’s shoes, so putting on shoes in the morning can easily get a bite. Therefore, if you are in the southern United States and if you left your shoes outside overnight, check in the morning that no one has settled in them.
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Rules of behavior in nature
Probably, once again, there is no need to describe the black widow spider; most likely, everyone who sees it will recognize it. In order not to become a victim of a predator, it is better to choose parking places where there are no animal burrows, where there is tall vegetation, that is, areas unsuitable for spiders to live. Do not sleep on open ground and walk barefoot in places where there are cobwebs.
When collecting brushwood and flowers, it is better to wear gloves and boots. If there are stones in the area, then you should not touch them with your bare hands or turn them over. Before going to bed in a tent, it is better to shake all things and bedding thoroughly.
The same rules apply for those who like to work in the garden: when getting rid of weeds, it is better to wear gloves and not leave shoes between the garden beds.
How to recognize a Black Widow bite
This spider injects its venom into its prey using its two front fangs, so close inspection reveals two tiny holes. Symptoms of a black widow bite: acute pain at the site of the bite, severe burning and numbness of the affected area.
Depending on the amount of venom injected, the person's age, health, and location of the bite, symptoms may vary. Common symptoms include headache, restlessness, weakness, possible nausea and vomiting, dizziness and sweating.
If you are bitten by Latrodectus mactans, the first thing you need to do is go to an ambulance or go to the hospital yourself. While you are waiting for help, you need to apply ice or something cold to the bitten area, this will reduce pain and swelling. If possible, take with you the spider that bit you; if it is dead, if it is alive, it is better not to catch it.
Antidote for Black Widow
To treat a bite, doctors use droppers with calcium gluconate and muscle relaxants; this is sufficient in most cases.
In serious cases, when there is a risk of death and it is not possible to transport the victim to the hospital, a special serum is used. But the use of serum is quite risky for the victim; it is practically not used for children under 16 years of age. Administration of the serum is possible only by a doctor and under his supervision, as urgent resuscitation may be required due to its allergic effect.
If you are bitten by a poisonous spider, always try to pick it up and put it in a jar. It will be easier for doctors to cure you, and treatment will be faster.
Black Widow Reproduction
Reproduction of a black widow is the same as that of all spiders, so we will not repeat it, in short it is courtship and sexual contact with the help of its legs. After mating, the female lays eggs; the incubation period lasts approximately 20 days.
Cocoon with black widow eggs, photo ru.wikipedia.org
During the mating stage, the female can kill the male. This feature is where its name, Black Widow, comes from. True, many species of spiders do the same.
What does it eat?
Like most arthropods, this predator eats other types of spiders and small insects caught in the web. These can be flies and mosquitoes, caterpillars and small bugs.
Typically, the female hangs upside down, boldly displaying her bright markings, but prey is rarely afraid of the spider's toxicity.
As soon as the victim finds itself in the web, the karakurt wraps it in threads and pierces it with its chelicerae. The spider's teeth contain digestive enzymes that allow the insect to dissolve. Now you can start eating and suck out all the liquid.
Another interesting feature common to most spiders: the black widow can go without food for a long time. There are known cases of “fasting” for up to 1 year.
