A female black widow spider (Latrodectus) hangs upside down in her web, showing a red hourglass on her abdomen. (Image credit: Kimberly Hosey/Getty Images)
Black widow spiders are several species of arachnids from the genus Black Widows (Latrodectus) that are known for the unique and striking appearance of their females, as well as a rumored tendency to eat their males. They are the most venomous spiders in North America; however, their bite is rarely fatal to humans.
Description and features of the black widow
The name “black widow” is given to both a genus and a separate species of spider. Karakurt spiders are often called “black widows,” but this is more their popular name than their official name. The arthropods got their name because the females kill the males after mating.
However, it is worth noting that many types of spiders are famous for this. The average life expectancy in nature is 1-3 years. In captivity, black widows live up to 4 years. The spider sees perfectly at night.
Let's look at what a karakurt spider looks like. This species has very pronounced sexual dimorphism. Males rarely grow more than 5-7 mm in body length. They have a dark brown or black color. The abdomen is elongated, with small red and white spots on its sides.
The paws of males are colored alternating orange and red. The size of females can reach 5 cm in paw span. They have a completely black glossy body. The abdomen has a rounded shape. Below it there are two bright red spots in the shape of an hourglass.
When writing a karakurt, it is also worth noting the strong long fibers on its legs. There are especially many of them on the last pair of walking legs. They are needed to pull together the web.
The main enemy for this spider is man. The black widow is very sensitive to chemical fertilizers that people use to treat fields. In addition, hedgehogs, wasps, and wasps are not averse to snacking on spiders. Apparently, the poison of karakurts does not affect sheep and pigs, which is why these animals often trample down the homes of spiders.
How many types of black widow spiders are there?
This is a northern black widow spider (Latrodectus Varolus), which was found in the leaves of a maple tree. (Image credit: NajaShots/Getty Images)
The Black Widow genus includes 31 species of spiders. Three North American species of spiders are collectively known as the black widow: the western species, the Western black widow (Latrodectus hesperus); northern species – Northern black widow (Latrodectus Varolus); and the southern species, the Southern black widow (Latrodectus mactans). ()
Black widow spiders belong to the family Theridiidae, and have a series of stiff, short hairs on the last segment of the fourth pair of legs that resemble the teeth of a comb. They are used to cover the prey with the web as the spider wraps itself around it.
The genus Latrodectus also contains red widows and brown widows.
- Kingdom : Animals
- Subkingdom : Bilaterally symmetrical
- Taxon : Protostomes
- Clade : Shedding
- Type : Arthropods
- Subtype : Chelicerates
- Class : Arachnids
- Squad : Spiders
- Family : Shadow spiders
- Genus : Black widows
(Source: ITIS)
Habitat of karakurt
Now let's look at where the black widow lives. This species prefers a moderately warm climate. Comfortable for it are areas with hot summers and warm autumns. It is widespread in Latin America, Africa, Central Asia, southern Europe and northern Africa.
The main habitats of the black widow in Ukraine and Russia: Donetsk and Rostov regions, as well as coastal areas of the Azov and Black Seas. The spider is found in Kazakhstan, Kyrgyzstan, Kalmykia, and Astrakhan.
The spider can also be found in areas with colder climates, but by winter it usually migrates to warmer climates.
Most often, the spider chooses for housing:
- hills, rocky slopes of ravines;
- wastelands, steppes;
- abandoned human habitations.
To hide, the spider prefers abandoned holes and mounds of dry leaves.
The black widow can crawl into human homes for the winter. You can stumble upon it in garages, sheds, outdoor toilets, and old abandoned houses.
To avoid being bitten, when walking in areas where this species is common, you should wear closed, tight clothing. The spider's fangs will not be able to bite through. It is better to work in the garden with gloves.
Lifestyle and habitat
Dangerous spiders can be found anywhere on the planet. They are especially widespread in Europe, America, Asia, Australia, and Africa. Until some time, the black widow spider in Russia
After all, he prefers a hot and temperate environment. But recently, these spiders have been seen in more than one instance in places along the Urals and in the Rostov region. The black widow lives in dark places, in dense thickets, in barns, basements, toilets, rodent burrows, and in dense vine foliage.
They lead a solitary nocturnal lifestyle and prefer to hide during the day. In general, they always try to remain unnoticed. As soon as the black widow senses serious danger, she falls out of the web and takes on a motionless pose, making it clear with all her appearance that she is not alive.
Without its strong web, the insect is helpless and clumsy. With the onset of cold weather, spiders approach human habitation. Therefore, it is necessary to show a photo of a black widow to your young children, who are characterized by increased curiosity and may, through their ignorance and carelessness, pick up an insect in their hands.
The peculiarity of the black widow spider is its furry legs. The strongest and having a large number of bristles. With their help, the spider tightens the web over its victim. It is not difficult to recognize the web of this insect. It has a chaotic weave and is mostly placed horizontally.
Effect of poison
Male black widows are not particularly aggressive. They prefer to run away rather than attack when danger appears. Females defend themselves with bites.
Karakurt poison is considered one of the most dangerous. It contains a neurotoxin, which spreads very quickly through the lymph throughout the human body. The degree of toxicity may depend on the season, the age of the spider and its gender. With timely assistance, death can most often be avoided.
A person does not always immediately notice that he has received a bite. The pain from it is commensurate with a pin prick. The first symptoms when poison enters the body:
- A small red dot forms at the site of the bite, which soon becomes invisible.
- Headaches and dizziness begin. Loss of coordination.
- Severe nausea, vomiting.
- The abdominal muscles contract involuntarily.
- Increased sweating.
- Severe pallor.
- My knees begin to tremble.
- Pain in the chest, back and abdomen.
- Shortness of breath, palpitations.
- No urination occurs.
If help is not provided in time, at the next stage the person will experience increased activity. He is trying to go somewhere and do something. Literally cannot find a place for himself. The person is very worried and does not calm down.
At a later stage, activity subsides. The person is in a depressed state. He has a confused mind.
Although death is not observed so often, if a person initially had a weakened immune system, he may die 3-4 days after the bite. Old people and children are especially vulnerable to poison.
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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Antidote
Black widow venom spreads quickly throughout the body. It is important to go to the hospital as soon as possible. The most effective method of overcoming the consequences of a bite is the administration of anti-karakurt serum.
The injection is given intramuscularly. You need 5-10 cubes of the drug. However, not all medical institutions have the vaccine.
Usually it is purchased only in those areas where black widows are often found. The cost of one vaccine is about $150. In addition, the shelf life of the antidote is very limited.
First aid for a black widow bite:
- the patient can be given a painkiller;
- A cold compress is applied to the bite site;
- a person should drink little but often;
- the affected part of the body must be immobilized so that the poison does not spread throughout the body so quickly.
In the first minutes, you can try to suck out the poison. But this can only be done by a person who does not have any damage to the oral cavity. Otherwise, he too may get poisoned.
If you are bitten by a spider, do not do the following:
- make an incision at the site of the bite;
- apply a tourniquet to the injured limb.
In the hospital, in order to reduce the harmful effects of toxins on the body, calcium chloride, novocaine and magnesium hydrogen sulfate are administered internally.
What does karakurt look like?
Karakurt looks like a medium-sized spider. Karakurt females are significantly larger than males in size. The female karakurt grows 2 cm in size, while the male karakurt is only 0.7 cm in size.
Karakurt looks quite unusual. The karakurt spider has a black body, and on its abdomen it has red or orange spots of various shapes. Both male and female karakurt have this coloration. Sometimes there may be a white outline around the spots. Often, upon reaching maturity, the karakurt spider can acquire a completely black color without spots.
Lifestyle
Black widows feed on insects and other types of spiders. It is believed that the web of this species is much stronger than silk. Karakurt weaves durable fabrics, which often catch grasshoppers, moths, butterflies and flies.
The spider itself hangs head down over the set trap. Bright spots on its abdomen scare away predators. When the prey gets caught in the net, the widow wraps it in the web using the fibers on her hind legs.
Afterwards, the spider's fangs pierce the upper integument of the victim and inject poison there. Like all spiders, karakurts have external digestion. As soon as the insides of the prey are digested, the predator will draw in the nutritious juice.
When it’s time to breed, the male karakurt performs a mating dance to attract a female. After mating, he is often eaten. Scientists suggest that this is how the female stores animal proteins before pregnancy. However, in nature, some males manage to escape from their girlfriends. They even manage to impregnate several females per season.
The female black widow lays her eggs in a cocoon made of cobwebs. She attaches it not far from her fishing nets and closely monitors that the cocoon is protected. There can be from 200 to 900 eggs inside it at the same time. It will take 2 to 4 weeks for the eggs to hatch. Only the emerging spiderlings are white. They will darken over the next few molts.
The young immediately begin to fight for life. Black widow cannibalism isn't just about females eating males. Young spiderlings are also not averse to snacking on their weaker younger brothers.
Thus, up to 12 spiderlings usually emerge from one cocoon. This happens in April, and in June the spiders become ready to reproduce.
Black widow - spider
Nutrition
Like many spiders, the black widow eats other arachnids and insects that get caught in its webs. The female hangs upside down and waits for her prey. This posture displays bright markings that are a warning to potential predators that it is toxic. The markings, however, do not scare the prey.
The spider eats flies, mosquitoes, midges, beetles and caterpillars. Once prey is caught in the net, the black widow uses its comb-like legs to wrap the prey in silk. Then it pierces its victim with its fangs and injects digestive enzymes that liquefy the corpse. And sucks out the liquid.
Interesting! Like most spiders, the black widow can live for a long time without food. Specimens have been known to survive for almost a year in the absence of prey.
Black widows are solitary all year round except during mating season. Young adults overwinter in buildings or in quiet outdoor areas. At the end of spring, after a long courtship, mating occurs. In some cases, the female kills her mate and begins to lay eggs
Spider activity
Its peak is recorded from July to September. During the migration of females (June/July), the number of people and animals affected by their “kisses” increases sharply.
Our karakurt, of course, cannot be compared with a real black widow in terms of the strength of its poison, but its bites are sometimes fatal.
So, in October 1997, karakurts bit 87 residents of the Kherson region: all of them were treated in a hospital, but one could not be saved.
Then zoologists suggested that the massive attack was provoked by rainfall, which drove the spiders out of their shelters.
Along the way, it turned out that in the post-war years the karakurt felt like the master of the Don steppes and disappeared for a long time due to their active development.
The revival of the black widow population began with the collapse of the USSR: they are actively breeding in abandoned fields and farms.
The second favorable factor is global climate change, in which the arid zone is moving north. This plays into the hands of spiders, who avoid heavy rainfall, which is disastrous for their burrows.
