How dangerous are yellow sakis and what can a bite from this spider lead to?

Yellow sak.
Frame youtube.com Residents of Bashkiria are concerned about the invasion of poisonous spiders - yellow cheiracanthiums or, as they are also called, yellow sakas. Near Ufa, after being bitten by such a spider, two men sought medical help, as reported by the news agency Bashinform. They were taken to the infectious diseases hospital, where they were given IVs and injections. Two similar cases occurred last year in the Ufa suburb of Nagaevo. One of the local residents' blood pressure rose after being bitten by a yellow sakura, and the man almost lost consciousness.

Question answer

Where did karakurt spiders come from in the Moscow region and why are they dangerous?

In the summer of 2022, yellow poisonous spiders appeared in the Rostov region. Residents of the Tatsinsky district discovered them in the courtyards of private houses and posted photos on social networks to warn their neighbors. And in 2014, the Oryol media wrote about the fact that yellow sak was discovered in the region. A resident of the region was bitten by a spider on the lip and hand; as a result, the woman went to the infectious diseases hospital, complaining of an unbearable burning sensation and acute paralyzing pain.

Do poisonous spiders live in Russia?

All kinds of arachnids are very widespread in Russia. Experts count more than a thousand different species. There are relatively few poisonous among them; they are found mainly in the wild. But recently, since their habitat is being actively destroyed by people, spiders are forced to migrate closer to homes. Therefore, an encounter with a poisonous individual on a personal plot cannot be completely ruled out. Spiders can also climb into a house or barn, looking for a secluded place for themselves.

Most of them prefer warm climates. In the south of Russia, the likelihood of encountering a poisonous spider is highest. But due to global warming, their habitat is expanding to the north.

Video: the most poisonous spiders in Russia, Ukraine and Belarus

https://youtube.com/watch?v=IWIaG366SfI

Lifestyle of yellow sak

Heiracanthium is nocturnal. Like other members of the Cheiracanthium genus, the spider uses its web only to create a cocoon, rather than spreading webs like a canvas to catch food. The spider hunts in the following way: it jumps on its prey, bites through the chitinous shell and injects poison. The poison paralyzes the insect, in addition, the yellow sak introduces saliva, it liquefies the insides of the victim, and the spider sucks them out.

The yellow pouch spider feeds on small insects and their larvae: aphids, moths, mites, etc.

The species is annual. Adults can be found from June to November (the period may vary depending on habitat conditions).

During the day, the spider hides in a cocoon and is practically inactive. The shelter of the yellow sak is among grass, low fruit bushes or flowers. The cocoon has one or two exits, which the spider closes during molting.

Features of reproduction

The breeding season usually occurs in July. In this case, the males create a cocoon directly on the female’s cocoon. After the female has her last molt, the male breaks through the closed passage of her cocoon and mates with her. Soon after copulation, the male dies.

Oviposition most often occurs in August. The female yellow saka creates a special dense cocoon that can reach the size of a chicken egg (4 cm in length) and has no exits. One clutch contains from 80 eggs to 295, depending on living conditions. The offspring hatch after 3-5 weeks (around September, less often in early October).

The female Heiracanthium fiercely guards her offspring and attacks any threat. The young remain in the cocoon until their first moult. In October or November, the adult female breaks the cocoon to release her offspring. Young spiders overwinter in small cocoons on withered leaves.

It should be noted that after laying eggs, the female stops hunting, which can be seen by her wrinkled abdomen. The female remains in the cocoon and dies there in late autumn. Sometimes you can find such cocoons even in winter.

By the way, it is typical for some species of Heiracanthium that the offspring eats their own mother.

The leader of the rating is Karakurt

Unanimously and objectively, the spider that is the most dangerous to humans and the only one whose bite, if timely medical care is not provided, leads to death, is considered to be the karakurt (translated from Turkic as “black widow”). This species of spider is thermophilic; its original habitat is the Black Sea region, the Caucasus, and the Southern Urals. Recently, it has been migrating further north, up to the latitude of the Moscow region, especially if the summer in central Russia is dry and hot.

Only the bite of a female is dangerous to humans. This is an individual measuring 1.5–2 cm (males are much smaller, up to 0.7 cm), black in color. On the top of its abdomen there are 13 small red spots with a white border, and on the bottom there is one spot resembling an hourglass. The combination of black and red in the world of insects is a color that signifies the poisonousness of an individual, so it is better to avoid any spider of this color. As they grow older, the spots disappear and the black widow, fully justifying its name, becomes glossy black.

Karakurt is aggressive by nature. He can attack on his own, and not just bite in self-defense. It is strongly not recommended to even approach it, much less tease it or take actions that the female may regard as a threat to the nest.

Karakurt is easy to identify by its characteristic pattern on its abdomen; it has exactly 13 red spots, but it is unlikely that anyone will want to get closer and count them

The karakurt bite itself is extremely painful. Within a quarter of an hour, local pain spreads throughout the body and intensifies, almost to the point of unbearable, sharp and burning. Other very unpleasant symptoms appear:

• breathing problems, feeling of heaviness in the chest;
• severe trembling in the limbs;
• muscle spasms;
• attacks of nausea and vomiting;
• dizziness, lightheadedness, feeling of loss of orientation in space;
• persistent migraine;
• tachycardia;
• increased body temperature;
• increased sweating, redness of the skin.

Chemical composition and mechanism of action of the poison

The poison contains protein neurotoxins, as well as enzymes - hyaluronidase, phosphodiesterase, cholinesterase, kininase. There is a species sensitivity to poison. Rodents, horses, camels, and cattle are very sensitive. Hedgehogs, dogs, bats, amphibians, and reptiles are insensitive. The toxicity of whole venom (LD50) is 62 for crayfish, 99 for houseflies, 205 for guinea pigs and 220 μg/kg for mice.

The main active principle of the poison is a neurotoxin (α-latrotoxin), a protein with M r

~ 118,000, consisting in the native state of two tightly bound subunits with a total M
r
~ 230,000 and p
I
5.2. The neurotoxin subunit molecule consists of 1042 amino acid residues. The LD50 of α-latrotoxin is 45 µg/kg for mice.

α-Latrotoxin is a presynaptic toxin. The point of application of its action is the presynaptic nerve ending, where the toxin binds to a protein receptor having M r

~ 95,000. At human body temperature (37 °C), a dimeric neurotoxin molecule binds to two receptor molecules, and this binding is very strong (
K
d ~ 0.1 nmol).
When the temperature decreases, the neurotoxin binds to only one receptor molecule, and less strongly ( Kd
~ 0.3 nmol).

The neurotoxin-receptor complex forms a channel for Ca2+, which enters the nerve ending and triggers the process of neurotransmitter release. Under the influence of the neurotoxin, a 1000-1500-fold increase in the release of the neurotransmitter is achieved, which results in 30-50 minutes. to the depletion of its reserves in the nerve ending and the development of a complete block of neuromuscular transmission. The depletion of neurotransmitter reserves is also confirmed by electron microscopy data, indicating the almost complete disappearance of synaptic vesicles during the second phase of the neurotoxin action. The ability of α-latrotoxin to induce the permeability of biomembranes to divalent cations is confirmed by experiments on bilayer lipid membranes.

In addition to α-latrotoxin, β-latrotoxin with M r was also found in the venom of karakurts (L. pallidus and L. dahli )

~ 75,000. The amino acid composition of β-latrotoxins from different karakurt species reveals a high degree of homology.

Other poisonous spiders found in Russia

The bites of other poisonous spiders that can be found in Russia are not life-threatening. But they can also cause a lot of unpleasant sensations.

South Russian tarantula (mizgir)

Leads a predominantly nocturnal lifestyle. Most common in the Astrakhan, Belgorod, Tambov regions. Despite the name, it is also found in Siberia. It lives in deep (40–50 cm) holes, lining them with cobwebs, but often climbs into houses.

The spider's shell and legs are covered with small, hard hairs. The color is different shades of gray, brown and brown; occasionally there are reddish specimens. The top of the body and limbs are painted with light and dark stripes.

The bite of this large (females - up to 3 cm, males - up to 2.5 cm) spider causes severe swelling, redness of the skin and pain comparable to those characteristic of hornet bites. General malaise, weakness, and drowsiness last for about a week. Often the situation is aggravated by an allergic reaction in the form of itching and a sharp burning sensation at the site of the bite. The skin around it turns yellow; the unnatural shade can persist for up to 6–8 weeks.

Exotic lovers often keep South Russian tarantulas at home; in this case, we must not forget that the spider is poisonous and the consequences of its bite are very serious

Heiracanthium

The most dangerous spider of those that originally live in central Russia. In the north it is found up to the Leningrad region. The color varies from dull yellow (often with a greenish tint) to cocoa color, the size ranges from 0.5–1.5 cm. The abdomen is teardrop-shaped, the front legs are twice as long as the body.

Reproduction

The male black widow, before going in search of a partner, weaves a small web and rubs the end of his abdomen against it so that drops of sperm appear on it. It then sucks up the sperm with its sexual organ, the pedipalps, which are like small feet. After this, the male is ready to meet his partner. He begins to shake his web as a sign that he is ready to perform a vital function. During sexual intercourse, the male uses the pedipalps to transfer sperm into the female's body.

Sometimes only one mating occurs, but the female can store the seed in her body and use it, for example, after a few months. After mating, the female weaves a silk cocoon in which she lays eggs. After some time, small spiders hatch from the eggs, which are miniature copies of their parents and soon become independent.

What to do if you are bitten

Often, at the sight of a large spider, people simply panic, causing an aggressive response in their address, which leads to a bite. First aid in this case is as follows:

1. If possible, take a photo of the “offender” so that you can identify him later.
2. Wash the bite area with warm water and soap for 3-5 minutes.
3. Apply a tight bandage above the bite site and apply a cold compress directly to it (this will slow down blood circulation, preventing it from spreading poison throughout the body). For the same purpose, it is necessary to minimize physical activity, normalize breathing, and calm down. Drink as much fluid as possible (including on the way to the hospital to reduce the concentration of toxin in the body).
4. To relieve the primary symptoms, take any analgesic; if you don’t have anything at hand, take regular aspirin. If you are prone to allergies, also take a tablet of a suitable antihistamine.
5. Go to the hospital as soon as possible for more qualified medical care.

The symptoms characteristic of a karakurt bite, even after the administration of a special serum, weaken, but do not disappear completely

Video: first aid for a spider bite

For a Russian gardener, an encounter with a poisonous spider is a rare, but not impossible, occurrence. Most of them are not aggressive by nature, so it is better to simply avoid a suspicious individual. In the event of a bite, it is necessary to go to the hospital as soon as possible; first aid measures can delay the spread and help remove the poison from the body, but they are not able to completely neutralize the toxin.

• Author: Yulia Golova
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Interesting Facts

• The male black widow is significantly smaller than the female. It is not dangerous to humans as it produces only small amounts of poison. The claws on the male's chelicerae are too small to pierce human skin.
• Karakurts were successfully bred at the London Zoo, where males mated with females many times and remained alive.
• There is an opinion that a black widow always eats the male after mating, but this does not always happen. The emergence of such an assumption is due to the fact that after several matings the male becomes so weakened that he is often near death. At this time, he cannot escape from the female, and the female eats him.
• In Europe, there is a karakurt, called by the Italians mal-mignatta. The Italian name has been adopted into several other languages. A karakurt bite is not as dangerous and painful as the bites of tropical species of spiders, but the consequences are noticeable for up to 3 weeks.

Habitat of the yellow sak

The species is found in territories from Central Europe to Central Asia. Due to warming, this spider can be seen more and more often in Russia. It was seen in the Krasnodar Territory, Voronezh Region, Rostov-on-Don, Tolyatti, Altai, etc. The exact habitat of the yellow sak is not currently established, since the features of its distribution have not been studied.

The yellow sac spider is considered one of the most dangerous spiders living in Germany. In 2022 and 2022 it was spotted in Bashkortostan, Tatarstan, Kazakhstan (Karaganda region), as well as in Russia (Chelyabinsk and Orenburg regions). In addition, the spider was found in Ukraine (Kiev region, Dnieper, Zaporozhye).

Lifestyle

Wasp spiders live alone or in small groups, the maximum colony size is up to 20 arthropods. They belong to the category of predatory spiders; their favorite diet is grasshoppers, dragonflies, and flies. Sometimes bees and wasps get caught in the snare, but then the battle flares up to the point of life and death. The unlucky hunter dies from bee (wasp) venom.

At dusk, a spider with yellow stripes on its back weaves trapping nets. He spreads a radial net, deftly connecting plant stems with spiral threads. A special “decor” is woven in the center or at the bottom of the web - stabilimentum - a thickened zigzag thread. Scientists interpret the purpose of this “pattern” differently - for camouflage, attracting prey, as a sign to relatives that the territory is occupied.

Interesting! The wasp spider is one of the fastest weavers. It creates a circular network with a radius of up to half a meter in 40–60 minutes.

After the work, the argiope sits on the stabilimentum and patiently waits for prey. The spider sprays poison into the victim, which paralyzes and turns the insides into a liquid mass. It is this “broth” that the predator sucks out, leaving only the chitinous shell of the insect. To maintain vital activity, the spider needs one successful hunt per week.

Black Eresus

Black eresus, or black fathead, is distributed throughout Eurasia, south of the forest zone. In the European part of Russia it is found on the edges of forests, in green meadows with sparse vegetation, as well as in birch and pine arid forests.

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Lives in a hole lined with cobwebs. Part of the web in the form of a tube comes out, forming a trap. The main food of the ladybug-like hunter is large insects caught in a trap tube. The black eresus leaves the shelter only to search for a partner. Therefore, it rarely occurs with humans.

The bite is extremely unpleasant. The person feels a sharp pain, and then numbness. For 2-6 days, the bite site continues to hurt when moving or pressing on the skin.