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The black widow spider (Latrodectus mactans) is considered the most dangerous spider in North America.. The spider got its name due to the fact that females periodically feed on their own partners. The name of the genus Latrodectus is translated from Greek as "biting in secret." The black widow is the largest spider in the family of shadowed spiders. (Theridiidae).
Adult spiders are painted black. On individuals, mainly red spots or a long red spot in the form of an hourglass are located. The body length of the female reaches 8-10 mm, the male - 3-4 mm, and weight - about 1 gram.
Despite its miniature size, a black widow can cause a lot of trouble to a person who disturbed her, because her poison is 15 times more toxic than rattlesnake. Fortunately, these spiders are not aggressive and do not attack a person for no reason, but only defending themselves, and a small amount of poison can rarely be fatal.
They are dangerous mainly for children, allergies, the elderly and sick people. Black widow venom containing a neurotoxin called α-latrotoxin causes severe muscle pain and cramping, “hard stomach”, increased blood pressure, nausea, vomiting, pain in the lymph nodes, intermittent shallow breathing and other characteristic symptoms. The pain can last up to a week. A healthy person is able to independently survive a bite, without the intervention of doctors, but in case of a bite, it is better to resort to the help of doctors. Before the invention of the antidote, the poison of this spider killed about 5% of the bitten.
Black widows are active in the dark. The main diet consists of insects and arachnids, which they catch in their thick durable nets. In small quantities, wood lice and millipedes become their victims. Spiders spin their web in dark, secluded places: near the ground, in piles of rubble, on fallen trees, around buildings and outbuildings. In cold and rainy weather, they look for places where it is warmer, so they can climb into a house or garage, especially if the buildings are abandoned. In the arid regions of Arizona, they live in crevices in the soil, in thickets of cacti and agaves.
Most of the time, black widow females hang upside down on their web and rarely leave it. During the summer, one female can lay from four to nine pear-shaped cocoons, each with 20-900 eggs, and from 9 to 15 cocoons in her entire life. The female actively protects cocoons with eggs until offspring appear.
Spiders hatch after 1-4 weeks, and, like their mother, are cannibals. Being in a cocoon, they eat each other, so only 1-2 spiders are selected into the wild. The newly hatched spiders are light and darken with each next molt. Puberty in black widows occurs at the age of 2-3 months. In nature, spiders live from 1 to 3 years.
Despite their toxicity, black widows benefiteating a huge amount of harmful insects, including mosquitoes - carriers of dangerous diseases, grasshoppers and locusts - pests of crops of grain crops. In addition, the web and poison are used by humans in biotechnology. An environmentally friendly insecticide and drugs for people with cardiovascular diseases are being developed on the basis of black widow venom.
Tramp Spider (Tegenaria Agrestis)
The question of whether this spider is dangerous to humans is still an open question. There are many alleged cases of a rogue spider attack whose bites cause tissue necrosis but pose no threat to life. However, they are extremely aggressive. An interesting fact is that this species moved relatively recently to the territory of North America. Previously, it lived throughout Europe, but, apparently, could not stand the competition with larger spiders.
Camel Spider (Solifugae)
In Russia it is known by the name of the phalanx. They look like they came from an arachnophobic nightmare and behave accordingly. Camel spiders are unpredictable, capable of accelerating to 16 km / h and their bite is extremely painful. Fortunately, they are not poisonous. They are found in any arid places, but for some reason are not at all common in Australia.
Yellow Spider Sak (Cheiracanthium)
A spider, barely reaching 10 mm in size, with its poison causes extensive tissue necrosis at the site of the bite. It is not fatal, but extremely painful. There is a golden spider in European countries, in Australia and Canada. Some experts believe that spiders of this species are responsible for more bites than any other spiders.
Ornamental Tarantula (Poecilotheria)
Tarantulas are huge hairy spiders from the family of wolf spiders. According to legend, these spiders are named after the dance, which, in order to cleanse themselves from the poison, people bitten by them had to dance. The bite of most tarantulas is not stronger than a bee sting, but the bite of an ornamental tarantula is very painful, and the poison causes serious swelling. It is found in the countries of Southeast Asia.
Mouse Spider (Missulena)
About 12 species of mouse spiders live in Australia. Armed with huge poisonous fangs - chelicera, which look rather menacingly, these spiders are not as dangerous as they seem. Their poison is dangerous for humans, but spider mice are not aggressive, and often, biting their victim, they make a “dry” bite without poison.
Six-eyed Sand Spider (Sicarius hahni)
Who lives in the deserts of Africa and has eight legs and six eyes? Right, six-eyed sand spider. Their poison is a powerful cytotoxin that can kill a rabbit in just five hours. This spider is undoubtedly dangerous for humans, but fortunately, it lives away from any human habitation. Only two cases of sand spider attacks on humans were recorded. Unfortunately, both are fatal.
Black Widow (Latrodectus)
One of the most "famous" species of spiders on the planet. Before the invention of the antidote, most black widow attacks on humans were fatal. Latrotoxin secreted by a spider causes blood poisoning. The victim suffers from bouts of vomiting and cramping in all muscles. It lives in North America and Australia.
Chilean Hermit Spider (Loxosceles)
The Hermit Spider gained notoriety after a huge number of photos appeared on the Web with the consequences of his bites. Its venom, penetrating the bloodstream, causes a gangrene scab at the site of the bite, nausea and fever. In rare cases, it leads to death. The brown hermit spider is actually not aggressive and attacks a person, only protecting its territory. It lives in North America.
Sydney Funnel Spider (Atrax robustus)
Sydney spiders are real giants among the rest of the spiders in the world. While most arachnids avoid humans, the funnel spider is aggressive and always ready for battle. His sharp chelicera can even bite through leather shoes or a nail and inject you with a decent dose of poison. A powerful neurotoxin causes muscle cramps, confusion, and cerebral edema. Fortunately, after the invention of the antidote in 1981, no deaths were recorded.
Brazilian Wandering Spider (Phoneutria)
In the Guinness Book of Records, spiders of this species are recorded as the most poisonous spiders in the world. The venom of a wandering spider is a powerful neurotoxin, 20 times more dangerous than the venom of a black widow. When it enters the bloodstream, it causes paralysis of the respiratory system and leads to a painful death from suffocation. It lives in South and Central America.
An ordinary spider is an animal with 6 pairs of limbs. But a person notices only 4 pairs of paws, since the first 4 limbs of the spider are transformed into organs of nutrition and touch. The body of the arthropod is divided into 2 departments: cephalothorax and abdomen. Both parts are connected by a short jumper. In a close-up photo of the spider, you can see that the cephalothorax is divided by a groove into two parts: the thoracic and the head. The limbs are located on the chest, providing the spider with movement and helping to weave the web.
Real spiders are always equipped with spinning glands.
On the head department are located:
- the first pair of limbs, converted into chelicera,
- the second pair of limbs - pedipalps, which perform touch functions and help the spider to catch and hold prey,
- mouth opening.
The number of eyes in spiders varies. The main mass of arthropod eyes is 8. Some species have a smaller number of eyes, up to their complete absence in spiders living in the eternal darkness of caves.
The reproductive organs in the male are also located on the pedipalps.
There is no complete circulatory system. Blood too. It is replaced by lymph. There are 3-4 holes in the heart that are called osty. Through the ostia of lymph from the body of the animal enters the heart, and from there through the arteries the heart drives the lymph into the spaces between the internal organs. From the gaps, the lymph enters the pericardial area of the body and returns again to the heart. Lymph has a mechanism that additionally supplies the spider with oxygen.
The respiratory system has a peculiar appearance. Lung bags have plates and look like books. The breathing openings that open the lungs are equipped with protective covers. There are also long tracheal tubes that transport oxygen from the openings to the organs of the spider body.
Being a predator, the spider has a well-developed central nervous system and a significant volume of the brain. There are 2 nerve nodes in the cephalothorax of the arthropod, from which many nerves diverge leading to the spider organs. These nodes are the brain of the animal.
The brain volume occupies 20-30% of the total volume of the cephalothorax.
Although spiders are obligate predators and they catch their prey on their own, but they have no teeth. To eat a prey, they need to dissolve its tissue and get a nutritious broth. This goal is served by spider venom, which the animal injects into the victim through hollow chelicera, achieving two goals: to kill still living prey and get a nutrient solution. Therefore, all spiders are poisonous, but few of them are dangerous to humans.
What are the spiders
Arthropods occupied almost all levels of living space on the planet. They can be found in burrows, on the ground, on bushes, on trees of any height. They did not master only air. And then conditionally. Some species spread on cobwebs, which they release in windy weather. A spider on a gossamer flying in the wind is able to overcome huge distances.
Unofficially, spiders can be divided into groups:
The familiar round web in the form of a “target” belongs to tree spiders. Burrowing webs fix the soil so that their home does not collapse. Ground "spread" a web on the ground, weaving pieces of soil into it. They use their web as a signal system. Subcubic live at the base of the bushes and weave a web in the form of a hut, which is masked by branches and soil.
Among fans of large tarantulas, there is an interesting division of pets into categories according to their speed characteristics:
- For beginners. Slow spiders that they like to demonstrate on video. These arthropods sit quietly in the palm of their hand, and if they try to escape, they move slowly.
- For advanced. If the spider of this group decided to escape, then the owner can only notice the direction in which the animal disappeared.
- For professionals. The escape of a spider is noticed by its absence at the place where he just sat. Where has gone, is known only to the arthropod itself.
The last group suggests that not all breeds of spiders have been discovered by scientists. It’s hard to see a fast spider, if you don’t even suspect that it is here.
In most cases, spiders do not pose any danger to humans. Is that annoying weaving cobwebs in the corners. But the classification according to the degree of toxicity is more practical, since there are some types of deadly even for humans.
- black widows, including karakurt,
- Brazilian runner spiders
- brown hermit spider.
Black widows are named so because the female eats the male after mating. Spiders of this genus are common on all continents. They catch prey using the web as a lasso. Not all species of this genus are dangerous to humans. The greatest celebrity was an American black widow.
North American Black Widow
There are 5 species of black widows on the northern continent. The main color of these spiders is black with red spots on the abdomen.
Not all black widows are black.
This kind of spiders can be distinguished by a characteristic line: long legs, which are clearly visible in the photograph.
North American Black Widow
A spider bite feels like a pin prick. After half an hour, muscle cramps appear, spreading throughout the body. Before serum, black widow bites killed 5% of the victims.
South American Black Widows
In South and Central America, 8 species live. The life and appearance of these populations are poorly studied, since the places where these spiders live are sparsely populated and have not been seriously studied.
18 species of varying degrees of toxicity live in Eurasia and Africa. In Eurasia, black widows spiders are called karakurt.
The name of the spider is of Turkic origin and in Russian means "black worm". The "classic" black karakurt Latrodectus tredecimguttatus lives in the southern regions of the continent, including the Mediterranean and Crimea. In connection with global warming, it began to come across in Azerbaijan, Altai and the Novosibirsk region. The ideal habitat for this Karakurt spider is warm autumn and hot summer.
The name and photo of the spiders are somewhat inconsistent with each other: this type of karakurt has large red spots on the dorsal side of the abdomen. The color can vary greatly: Eurasian species interbreed and the spider can be pure black.
Karakurt black and white
There is a white karakurt (Latrodectus pallidus). Since white karakurt look uncharacteristic for these types of arthropods, you can not pay attention to them. White karakurt are less toxic than black ones, but their bite can cause trouble for children or people suffering from allergies. The habitat is combined with the territory on which black karakurt lives.
It lives on the North American continent. The leg span can be 6-20 mm. Color brown, dark yellow, gray. One of the species in which the eye is less than 8. The hermit has only 3 pairs, which can be seen in a close-up photo of the cephalothorax.
He leads a nocturnal lifestyle, hiding under roots and stones during the day. The hunting method is active, but weaves nets that it uses as a shelter. Likes to settle in a person's housing. Can accidentally get into bed at night. If pressed down, it will bite.
The consequence of bites is the development of a necrotic ulcer. Heals the affected area for 3 years. A bite can lead to death if the victim is a child or a person with a weakened immune system.
Spiders of medium toxicity
The bite of such arthropods does not lead to death, but can bring trouble in the form of swelling of the extremities and a painful bite. These types include:
Bites of these animals cause local irritation. With a very large dose of poison, swelling of the limb is possible.
Large tree spiders, spinning the largest cobwebs. They have several names:
- banana spider
- giant tree spider
- gold spinner.
Body length 1-4 cm. Paw span 12 cm. Poison for humans is not fatal. A spider bite causes a local allergic reaction: burning, the appearance of blisters, redness of the bite. Symptoms go away during the day.
Belong to the family of wolf spiders. Two species are best known: the South Russian and the Apulian tarantula. The common name of the South Russian tarantula is misgir spider. Large arthropods, not weaving hunting nets. They lead a nocturnal lifestyle, attacking small invertebrates and other spiders. During the day they hide in vertical burrows with a diameter of 1-1.5 cm and a depth of 0.6 m. Animals have a gray protective color. The abdomen is covered with bristles. Paws of medium length.
Distributed in the southern dry steppes of the Eurasian continent. Tarantulas are especially poisonous in the spring after hibernation, until they have time to squander the poison. But you have to try hard to get a bite from this arthropod: first remove it from the hole, and then grab it with your bare hand. Defending itself, the tarantula is capable of a vertical jump, but at the first opportunity it will try to hide.
In English-speaking countries, tarantulas are called large tarantulas.
The second name is yellow heyrakantium. Originally an inhabitant of the southern regions. But the abnormal heat led to the fact that arthropod began to be found in Central Russia. The spread is facilitated by the unhealthy addiction of sake to the smell of oil. He often gets between the tubes of the motor system of the car. Clogs the ventilation holes with its web.
Small animal: 0.7-1.5 cm. Paw span reaches 2.5 cm. The color is yellow-brown. It has impressive chelicera with very long needles. This device is for active night hunting. What sak looks like, you can see the spider photo below.
Saka poison causes soft tissue necrosis. Other signs of poisoning can be nausea, headache, fever. The bite site becomes inflamed.
Она же паук-оса. Относится к семейству пауков кругопрядов. Свое имя «оса» получила за характерную окраску брюшка. По числу видов уступает только паукам-скакунам и линифиидам. Ареал аргиопы ограничен 52°с.ш.
Аргиопа – один из видов, освоивших полет на паутинке.
Охота пассивная. В сумерках плетет ловчие сети круглой формы. Питается летающими насекомыми. Укус болезненный. Может вызвать местное раздражение.
Representatives of this group either cannot bite through human skin, or their poison is too weak to cause harm. These spiders include:
Most spiders are not interested in humans. They live in nature and desire only one thing: that no one touches them.
The largest spiders. The champion of the largest arachnids in the world is the goliath spider: a tarantula whose body length reaches 10 cm. Goliath's paw span is 28 cm. The body is covered with thick red-brown bristles. A tarantula is not dangerous to humans, but falling bristles can cause an allergic reaction.
Crosses are large spiders with a very large abdomen of a triangular shape. On the back there is a characteristic pattern in the form of a cross, which gave the name to the entire family of spider-spiders. Inhabitant of gardens, forests, parks and other green spaces. Conducts a passive hunt for insects, weaving circular nets. The cross itself makes a refuge from folded leaves.
Bites are harmless. Even a child feels like a light pinch. But to stop the baby from grabbing the spider with his hands, the cross is able to.
Haymakers have already become not domesticated spiders, but “domesticated” and in no way want to leave a person’s housing. For people, they are completely safe and cannot even pinch. Outwardly, the grassland is similar to a rhino-bug, but has an elongated body, divided into two parts. The bug has a round body.
The haying spider weaves a messy web in all corners with murderous industriousness and annoys people not with bites, but with the need to constantly remove the fruits of his labors.
Belongs to the funnel spider family. Distributed everywhere. Often settles in the dwelling of a person. The female house spider is 7-12 mm in size, the male is 6-9 mm. The color is brown. Funnel network weaves. It’s not aggressive towards people, but if you put your finger in his shelter, it can bite. There will be no consequences from a bite.
Horse spiders are one of the largest families. Distributed everywhere except Greenland. Spiders of this family are capable of jumping and are actively hunting in the daytime. The horses have a well-developed hydraulic system that allows them to change blood pressure and expand their limbs. Thanks to this device, they can make jumps that are many times larger than their own size.
The family of horses is remarkable in that it has the only species of spider - a vegetarian. Bagira Kipling lives in Central America and feeds on acacia genus Vachellia. But this spider is not a pure vegetarian. During a period of drought, they can switch to food by individuals of their own species.
The original Australian endemic from the family of horses. A small spider of very bright coloring. The name peacock spider received for a complete copy of this bird: a bright male and a modest female. Caring for the female, the spider "spreads its tail." He spreads the side shields of the abdomen and raises his hind legs with the abdomen up. In the absence of a female, spiders wrap shields around the abdomen.
Vagabond spiders got their name because they do not weave nets and hunt, attacking prey from an ambush. The structure of the eyes and hunting methods are similar to wolf spiders. The female uses a web for weaving a cocoon, in which she seals the eggs. The female carries the cocoon with her on her back.
Belongs to the family of sparassids - hunter spiders. The body can reach a length of 2 cm. Color variations from tan to dark brown. On the sides of the body is a white stripe. Distributed in a temperate climate in Eurasia. It lives on the banks of water bodies. A distinctive feature of the hunter's spider is the ability to move around the water and even dive in case of need. The second name of the hunter is a fisherman, since a spider can catch and kill small fish. He does not care about a person.
It is impossible to determine the toxicity of this arthropod, since the nature of the species "green spider" does not exist. Different animals from different genera have this color:
All these green spiders are in Russia. To decide how dangerous the bite of a green spider is, you first have to find out which family it belongs to.
It is also difficult to determine what kind of crab spider we are talking about. Arthropods from three families have the ability to move sideways at once:
- Thomisidae (sidewalk spiders),
- Philodromidae (isopods side walkers).
A separate type of “crab spider” does not exist, but all spiders from these three families are not dangerous for humans.
In the arid regions of Central Asia and Africa, large arthropods live, which are often mistaken for spiders. These are salpugs. According to tracing paper from English, they are also called camel spiders. But unlike spiders, salpugs have teeth, they have no spider glands and are not poisonous.
Solpuga is a large animal that can catch and kill not only invertebrates, but also small lizards. The large salpug chelicera are so powerful that they can bite through a human nail. No real spider is capable of this. Although the salpugs have no poison, their bite can be very dangerous. Particles of decaying flesh remain on the chelicera of these arthropods. After a bite, you can get blood poisoning.
Spiders cause arachnophobia in many, although they are one of the most harmless and useful inhabitants of the planet. Fans of spiders consider them “kittens”.