Brown recluse spider (lat. Loxosceles reclusa)

One of the most poisonous spiders The world is considered the brown recluse spider. Scientists classify it as an arthropod arachnid of the spider order, family Sicariidae. The genus this spider belongs to is called Loxosceles.

Poisonous spiders are the most dangerous animals for us. They sneak up unnoticed and can strike what is called “in the back.” Who would want to become a victim of this eight-legged creature? There are probably few people willing!

If a person does happen to be bitten by this insidious creature, then tissue necrosis occurs at the site of the bite, which is deadly!

What does this little eight-legged monster look like?

This hermit spider is small in size. If he straightens his paws, then their span is from 6 to 20 millimeters. It is not always possible to even notice this deadly spider right away. Females are larger in size than males.

Body color is predominantly Brown color. But there are also yellow and gray representatives of this species. On the upper part of the cephalothorax the recluse spider has something resembling a violin.

A distinctive feature of this species is the presence of only 6 eyes, instead of 8. The abdominal part and paws are covered with small hairs.

In what part of the world can we expect this creature to attack? In other words, where does the brown recluse spider live?

The territories of his residence are considered to be: the midwestern United States. Further, the range goes south – to Gulf of Mexico. But the state of California was not included in the list of its “homes,” although representatives of arachnids similar to the brown spider live there.

Lifestyle of a recluse spider

Brown recluse spiders are nocturnal predators. Like most spiders, they weave spider webs that catch their prey.

Almost the rest of the day, except at night, they sit out in secluded places - among the roots, under stones, in rodent burrows. But sometimes they become close “neighbors” of people, which is a very dangerous circumstance for the latter.

What does the insidious spider eat?

All living things that fall into his web and become food for him. Basically, its prey is insects, as well as other spiders.

Reproduction of poisonous hermits

In secluded places, away from prying eyes, the female brown recluse spider lays eggs. The eggs are located in a whitish sac, “woven” personally by the female from a web, the size of which can reach 7.5 millimeters in diameter. During one mating season, 30 to 50 eggs are laid.

Once born, young individuals undergo many molts before reaching adulthood. Each molt for a spider is a very unpleasant and even painful condition. Maybe that's why some spiders are so angry and bite so painfully?

IN natural environment Brown recluse spiders live up to two to four years.

A week later…

How to protect yourself from a recluse spider bite?

In fact, these eight-legged creatures are not aggressive at all; they themselves rarely attack without reason. But if you disturb a spider... for example, when it got into the laundry and you started cleaning... you shouldn’t expect mercy - it will bite!

Immediately after a brown spider bite, tissue necrosis occurs, that is, tissue death. Typically an adult healthy person with a strong immune system, nothing threatens you except an unpleasant wound, of course, if you consult a doctor in time. But small children and elderly people, as well as sick people, are less fortunate. Their body is not able to resist the toxins contained in the spider's venom as easily. Therefore, there have been cases of death.

Brown spider-hermit is one of the most poisonous representatives of the family of brown recluse spiders, famous for its venom, which causes necrosis (death) of tissue at the site of the bite.

Residents of the eastern part of the United States are “lucky” to have such spiders in their neighborhood. This species is distributed from the midwestern United States to the Gulf of Mexico. It is not found in California, but other members of the genus Loxosceles live there. One of its relatives, the red recluse spider, is found in Hawaii.

They live quietly and do not bother anyone unnecessarily. They spend most of their time hiding in secluded places: in crevices under stones and tree roots, in burrows of small animals and other crevices of natural origin. But due to the development by man of their ancestral habitats, over several hundred years spiders have learned to live next to him. True, this “joint” living clearly does not warm a person’s soul. This is understandable, who would be pleased to find this small, but quite dangerous, 8-legged creature in their bed or in their closet with clothes.

Photo by Spiderman937

And the spider is happy to try. He spins his nets in any suitable place - in sheds among firewood, in garages, basements and attics, that is, where there is wood and twilight. Sometimes it crawls into the house itself, where it gets into things collecting dust in the corner.

It is not always possible to notice it right away. He has small sizes– body length in leg span can reach 6-20 millimeters. The females are a little larger. And the color of the spiders is suitable: brown, gray or dark yellow. On the top of the cephalothorax there is a pattern shaped like a violin, but this is not distinctive feature of this type. Similar designs can also be worn by representatives of other families of arachnids.

Photo by Roy Dunn

Another feature of these spiders is the presence of 3, rather than 4, pairs of eyes. The abdomen and legs are covered with short sensitive hairs. The legs are long and thin, in a calm state, widely spaced.

These are nocturnal spiders. They go hunting in the dark. Males calmly leave their web and go to explore distant surroundings, but females are not so willing to take this step. They try to hunt close to their “home”. It is precisely such night raids in search of prey (they hunt insects and other spiders) that bring hermit spiders into human homes. That's when His Majesty Chance comes into play.

This spider itself is not aggressive and will rarely attack a larger object first. A bite can only be inflicted in cases of self-defense. Most bites occur during cleaning or before bed, when the spider climbs into clothes scattered on the floor or into the bed.

The consequences of this bite will depend on the amount of poison that has managed to enter the body. There are times when everything goes unnoticed and without serious consequences. But if there was a lot of poison, then the most unpleasant things begin.

Photo by Kurt Nordstrom

The bite of this spider leads to a disease such as loxoscelism, the main symptom of which is extensive necrosis of the skin and subcutaneous tissue. The disease is accompanied by constant malaise, nausea, fever and other unpleasant sensations. The size of the ulcer can reach colossal sizes - up to 25 centimeters in diameter. After healing, ugly depressed scars then remain at the site of such wounds. In severe cases, necrosis can affect more than just tissue skin, but also internal organs. This happens, of course, very rarely, but still. There have also been cases of death (in small children, elderly people and people with weakened bodies).

Loxoscelism

But what it can lead to if you don’t see a doctor in time.

On the 3rd day after the bite
On the 4th day after the bite
On the 5th day after the bite
On the 6th day after the bite
On the 9th day after the bite
On the 10th day after the bite

To avoid such an outcome, people living in the habitat of these spiders must adhere to a few simple rules:

1) keep order in the house and do not scatter your things everywhere,

2) check your clothes and shoes thoroughly before putting them on,

3) frequently carry out wet cleaning and remove all dust and cobwebs from the far corners,

4) seal all cracks and cracks through which spiders can enter the house,

5) install special lamps on the outside of the house that repel insects that the spider feeds on, etc.

Scar at the site of a spider bite

In these same places, hidden from the human eye, they store their masonry. The female lays eggs in the form of large whitish sacs. Its diameter can sometimes reach 7.5 millimeters. It contains from 30 to 50 eggs inside. Spiderlings have to molt up to 5-8 times during their growing period. The shed skin is very hard and can be stored in the ground for a long time.

The lifespan of these spiders ranges from 2 to 4 years.

The brown recluse spider, whose name in Latin is Loxosceles reclusa, is a highly poisonous arthropod.

The consequences of its bite can be extremely dangerous to human health. In this article we will look at what a recluse spider looks like, the dangers of its bite, and how to help a victim of its poison.

Appearance and dimensions

Recognizing a recluse spider is relatively easy:

1. Despite the name, the body of Loxosceles reclusa is not always brown in color - it can be gray or brownish-yellow. The size of females in this species is slightly larger than the size of males.
2. Representatives of this species of spider have an unusual marking - a brown spot in the shape of a violin. This is a feature of adult hermits, but sometimes it is also present in younger individuals.

   Did you know? Arachnophobia is the fear of representativesa squad of spiders. This phobia is one of the most common in the world and affects approximately 10% of men and 50% of women. The severity of the phobia can vary in one direction or another.

3. A clear difference between the brown recluse and other arachnoids is the number of eyes. He has only three pairs of them, while other spiders have four, i.e. 8 pieces.
4. In a calm state, the hermit’s paws are placed on the sides of the body, but in case of alarm, he immediately takes a protective position: he pulls his front legs under him, raises his pedipalps and straightens his hind limbs.
5. The back color of adult Loxosceles reclusa varies from tan to dark brown.
6. The belly and legs are evenly colored, without stripes or spots. The legs are long and thin, without noticeable spines. The abdomen is covered with fine, short hairs that, when viewed without magnification under a microscope, may appear like soft fur.
7. The joints of the limbs are slightly lighter in color than the legs.

Where does he live?

Loxosceles can live almost all over the world in warm, tropical regions. This species is common in some areas of the United States of America (Southern California, Colorado, New Mexico).

The appearance of these spiders in other countries can happen by accident - they are transported along with cargo by air or across the ocean. They have not yet been seen in Russia and Ukraine. In nature, brown recluse spiders live outdoors under rocks, logs, and woody debris.

The spider can also live in the same room with people. Hermits are resilient enough to survive winters in unheated basements or stifling summer heat in attics, going for months without food or water.

During the daytime, brown recluse spiders usually hide in dark, secluded places, living up to their nickname. Adult females rarely travel far from their shelter, while males and young females are more mobile and prone to long-distance travel.

Video: about the recluse spider They are the ones who often get into shoes, clothes or beds at night and bite people when accidental contact between the spider and a person occurs.

Sometimes Loxosceles reclusa can be seen during the daytime - they move along the floor, walls and other open surfaces. This behavior may be caused by hunger, pesticide use, or other factors.

How to hunt and what to eat

Loxosceles reclusa hunts at night, catching insects. It does not use a web to capture prey - webs on walls, ceilings, bushes or trees almost always belong to harmless spiders.

Their presence in the house is also unpleasant for many people, but these spiders also hunt brown recluses, thereby bringing benefits.

Loxosceles reclusa is a small spider, does not produce hunting nets, so it hunts its prey in the classic way: it catches up, attacks, injects poison and immobilizes it, killing the victim with poison.
The venom of the brown recluse is lethal to insects - it is very toxic substance, the nature of which is not fully understood. Loxosceles reclusa hunts only on small insects whose size is much smaller than its own.

Did you know? With the exception of one family (Uloboridae), all spiders are poisonous. They use venom to obtain food and when they bite their prey, they squeeze their venom glands, sending the venom through their fangs into the victim's body. Spider venom paralyzes prey.

Reproduction

Spiders lay their eggs on a bed of silk, which they prepare immediately after mating. As soon as the clutch is completed, the female covers it with a large amount of web, which makes the cocoon dense and waterproof. Cocoons look like whitish round bags, the size of which does not exceed 7–8 mm.

Each cocoon contains about 40–50 eggs. After hatching, the baby spiderlings grow, gradually increasing in size, molting five to eight times as they mature before reaching sexual maturity.
Loxosceles reclusa become adults approximately a year after birth and live from 2 to 4 years. Females lay up to 5 egg cocoons throughout their lives. Infestation levels of these spiders in homes vary greatly, from the presence of one or a few specimens to several hundred.

Consequences and help with a bite

Like other spiders, the brown recluse is not aggressive. The majority of accidents occur if a person accidentally crushes the spider and the arachnoid comes into contact with bare skin.

Some people may be bitten in bed, other bites occur when moving things and pieces of furniture, or when a person puts on clothes that the spider has recently chosen for its daytime hiding place.

Loxosceles reclusa have very small mandibles and cannot bite through clothing. Initially, the bite is painless. Often the victim does not become aware of the bite until the bitten area becomes red and swollen 3 to 8 hours later.
Most spider bites remain localized and recovery occurs within 3 weeks without serious complications or the need for medical intervention.

In other cases, the victim may develop a necrotic lesion, which appears as a dry, bluish patch on the skin with jagged edges, a pale center, and peripheral redness.

Often there is an ulcer within the lesion. As the venom continues to destroy tissue, the wound may grow larger over several days or weeks.

If subcutaneous fat necrosis has begun, it may take up to three years. Complications include local nerve damage and secondary infection. A necrotic ulcer leaves a deep scar after healing.

Often bites on early stages(in the first 72 hours) cause in people:

• fever;
• chills;
• dizziness;
• rash;
• vomiting;
• weakness;
• headache;
• myalgia;
• arthralgia;
• maculopapular rash and leukocytosis.

Sometimes hemolytic anemia, hemoglobinuria and renal failure develop, which can lead to death. The wound must be washed, a sterile bandage and a cold compress applied.

Important!Severe reactions to Loxosceles reclusa venom are more common in children, the elderly, and patients in poor health.

The affected limb should be immobilized, it should be given an elevated position, and if necessary, analgesics and antibiotics should be administered. Anti-spider poisoning serum is effective but not approved for use in all countries. The drug can be used only after the inflammation has subsided.

Difficulties in diagnosis

Spider bites are difficult to diagnose even for doctors. It is especially difficult to do this, relying only on appearance wounds.

Externally, a necrotic wound is very similar to the consequences of other diseases:

• bacterial and fungal infections;
• gangrene;
• diabetic or peptic ulcer disease;
• outbreak of the bacterial infectious disease Staphyloccus aureus.

The brown recluse spider (Loxosceles reclusa, in English - Fiddleback Spider, or Violin Spider) is the most poisonous member of the brown recluse spider family.

Its venom can cause necrosis (death of tissue) at the site of the bite.

Thus, in terms of the degree of poisonousness, it can be put on a par with such spiders as, Australian and even.

Features of the view

What they look like

Despite the species name, the body of Loxosceles reclusa is not always brown - it can be dark yellow or gray. The females of this insect are slightly larger than the males (the span of the legs is from 0.6 to 2 cm).

A striking feature of the family is dark pattern on the back, resembling a violin in outline(“the neck” is directed downwards). Although this pattern can also be found in closely related forms and even in other representatives of the arachnid genus, it is the brown recluse that is sometimes called the Violin Spider.

But where this poisonous animal really differs from its relatives is the number of eyes. Most spiders have 8 of them, but the recluse has 6: one pair in the center and two on the sides.

Typically, the Fiddleback Spider's legs are spread wide apart, but when danger approaches, it instantly takes a defensive position: it draws its front legs inward, raises its pedipalps (the second pair of legs), and extends its hind legs to jump.

Reproduction

Female brown recluse spiders lay their eggs in white sacs and store them in hidden places. Each such sac, about 7–7.5 mm in size, contains 40–50 eggs. Before reaching adulthood, numerous brown recluse cubs change their outfit to a more spacious one, shedding their chitinous cover at least 5–8 times.

Discarded spider skins have a rigid structure, remain in the ground for a long time and are often used for identification by arachnologists when studying this type of insect. The lifespan of Loxosceles reclusa is from 2 to 4 years.

What do they eat?

Unlike other spiders, brown hermits do not weave clearly structured “lace” trapping nets, making do with simply randomly scattered threads. They feed exclusively on small insects that fall into placed traps, so obtaining food is not particularly difficult for hermits. It remains a mystery why nature needed to endow this insect with such a potent poison.

Where do they live?

Brown recluses range across the United States from the Midwest to the Gulf of Mexico, from southeastern Nebraska through Iowa, Illinois, Indiana, and southern Ohio, and from Texas through western Georgia and to northern Virginia. Contrary to popular belief, this spider has never been seen in California - only its relatives from the loxosceles family are found there, and in the Hawaiian Islands - the red loxosceles rufescens. In the 70s of the last century, Loxosceles reclusa was brought to Australia from the USA.

For most of its life, the brown recluse spider hides in secluded corners: among the roots of trees, under stones, in animal burrows. But due to the development by people of their permanent habitats, these spiders had to change their way of life. Little by little, they adapted and began to feel like full-fledged neighbors of people, settling in basements, garages, sheds, attics and toilets, as well as underground - in sewer pipes. Often, hermits get very close to a person: they penetrate apartments and houses, finding refuge in shoe boxes, under furniture, behind baseboards. They really like places where there is twilight and trees.

What is the threat to a person from meeting Loxosceles reclusa?

The recluse spider is not aggressive towards humans. These insects generally never attack a larger object than themselves, but bite only for self-defense. Most often, this poisonous insect infects people who are careless and disturb the spider in its “hole”, for example in a bed, in a closet, in shoes or somewhere among old trash. The spider regards the intrusion as an attempt on its territory and attacks. As a rule, the arms, neck or lower abdomen are bitten.

What to do if you are bitten?

Immediately after the bite, it is necessary to quickly prevent the spread of the poison: treat the wound with an antiseptic, apply ice and immediately go to the hospital. If a limb is affected, it needs to be elevated. It is advisable to catch the spider, put it in a tightly closed container and present it to the doctor for identification.

Previously, doctors removed tissue damaged by the bite, but now treatment is carried out in more gentle ways: with the help of a course of hormone therapy and antibiotics.

If treated in a timely manner, antivenom serum is also used.

There are many other ways to treat bites with varying degrees of effectiveness: dapsone, antihistamines, nitroglycerin, vasodilators, heparin and even electric shock. None of these methods have been specifically studied to determine their effectiveness. In most cases, the consequences of brown recluse spider bites can be cured with traditional medications.

Consequences of a bite

The consequences of a bite directly depend on the amount of poison that the spider manages to release into the body of its victim. If the amount is small, a person may not even notice the bite, and there will be no unpleasant consequences.

It’s another matter if the hermit manages to do his “dirty deed.” The bite itself will not be very painful, similar to a weak needle prick, but after, within 2–8 hours, painful sensations will increase. The venom of spider violin has a hemolytic effect and causes tissue destruction and necrosis, sometimes even penetrating into internal organs. For children, sick or elderly people, the bite can be fatal.

After a bite, a gangrenous scab appears at the site of the lesion. The condition gets worse:

• nausea,
• fever,
• malaise,
• thrombocytopenia,
• hemolysis.

The combination of these characteristics is known as loxoscelism.

When hit large quantity poison in the tissue, necrotic ulcers form, which grow to 20–25 cm in diameter, destroying soft tissue.

After healing, which usually lasts from 4 to 6 months, a depressed scar remains on the body.

inspect the bed before going to bed;

do not keep empty boxes and various rubbish under the bed;

regularly remove cobwebs;

seal cracks and cracks through which insects can enter the house.

Science knows only a few species of spiders whose venom can cause tissue necrosis. These include, in particular, Tegeraniaagrestis - the American wandering spider and Cheiracanthiumpunctorium - the pouch spider. But, unlike the brown recluse spider, they never cause such serious injuries to humans. This suggests that Loxosceles reclusa is extremely dangerous.

American scientists from the Institute of Geology and Biodiversity are trying to develop a so-called method. modeling ecological niche, which will help predict the spread of this type of insect and improve the treatment of bites.

Appearance

The leg span is 6-20 mm, females are slightly larger. The body is colored brown, gray or dark yellow. The dorsal side of the cephalothorax usually bears a dark pattern resembling a violin (the neck is directed towards the posterior end of the body). The presence of such a pattern is not unique for this species, and is common not only among closely related forms, but even among representatives of other families (for example, hay spiders).

Cephalothorax Loxosceles reclusa. Three pairs of eyes and a pattern resembling a violin are visible.

Unlike most spiders, which have eight eyes, this type characterized by the presence of six eyes, organized into three pairs: one medial and two lateral. From other spiders with six eyes (family Scytodidae) is distinguished by the absence of color patterns on the abdomen and limbs. The abdomen is covered with short hairs. The legs are somewhat lighter in the joints.

The legs of a recluse spider are widely spaced if it is on a flat surface, however, when alarmed, it takes a defensive position: it draws its front legs inward, raises its pedipalps, and extends its hind legs to lunge.

Life cycle

The spider lays eggs in the form of sacs white and stores them in well-covered places. Each sac is approximately 7.5 mm in diameter and contains 40 to 50 eggs. Baby spiders shed their chitinous covering five to eight times before adulthood. The shed cover has a very rigid structure and can be used for identification by experienced arachnologists. The brown recluse spider lives from two to four years.

Lifestyle

During the day, the brown recluse spider hides under stones and snags, in crevices and burrows of small animals, and at night it hunts for other spiders and insects. . He injects poison into his victims, which has hemolytic and necrotoxic effects. Unlike most spiders, the brown recluse spider leaves its web at night. Males spend most time hunting, while females prefer to be closer to their networks.

Habitat

The brown recluse spider thrives when modified by humans. environment. It weaves random webs in armfuls of firewood, as well as in sheds, garages, basements, attics, toilets, plenum cavities and other places where there is wood and twilight. They can also be found in empty boxes, shoes, clothes, bed linen, behind pictures and behind skirting boards - in a word, in those places that are identical natural place The habitat of the hermit spider is tree bark, burrows, crevices, etc. In rooms with low temperatures, the spider tends to heat sources.

Spreading

The distribution of this species is from the southern midwestern United States to the Gulf of Mexico. The range lies along a line from southeastern Nebraska, through southern Iowa, Illinois, Indiana, and into southwestern Ohio. In the southern states - from central Texas to western Georgia and northern Virginia. A related species of the brown recluse spider is the red spider (lat. loxosceles rufescens) - found in Hawaii. Contrary to popular rumor, the brown recluse spider is not common in the state of California - other species from the genus Loxosceles are found in the southwestern United States and California.

Danger to humans

The brown recluse spider is not aggressive and rarely attacks humans. He usually bites people when they encroach on his life and territory. Most people get bitten due to carelessness and inattention during the cleaning process. This usually happens when a spider gets under clothing or on the bed. Some people are bitten by a spider right in bed, others - when they put on shoes or clothes in which this representative of the arachnids is hiding. The arms, neck and lower abdomen are usually affected.

Poisonous Bite

Tissue necrosis caused by a spider bite

A spider bite very often goes unnoticed, but in most cases the sensations are similar to those of a needle prick. Then, within 2-8 hours, pain and itching make themselves felt. Further, the situation develops depending on the amount of poison that enters the blood.

The bite of a brown recluse spider causes a range of symptoms known as loxoscelism. It is characterized by a gangrene eschar at the site of the bite, nausea, malaise, fever, hemolysis and thrombocytopenia. In most cases, a spider bite is insignificant and does not cause necrosis, but in large doses it can provoke the formation of a necrotic ulcer that destroys soft tissue. The diameter of the ulcer can reach 25 cm or more, and after healing, which takes 3-6 months, a depressed scar remains.

The clear, viscous venom of this spider contains esterase, alkaline phosphatase, protease and other enzymes that cause tissue necrosis and hemolysis. The main role in the development of necrosis belongs to sphingomyelinase D, which binds to cell membranes and causes neutrophil chemotaxis, vascular thrombosis and the Arthus phenomenon. In case of necrosis of subcutaneous tissue, healing may take 3 years.

In rare cases, systematic symptoms are characteristic: damage internal organs and, in extremely rare cases, even death; majority deaths seen in children under seven years of age, people with weak immune systems, and the elderly. The causes of death can be hemolytic anemia, hemoglobinuria and renal failure.

The medical literature lists several spiders whose bite leads to necrosis. These include, for example, the American wandering spider (lat. Tegenaria agrestis) and bag spider (lat. Cheiracanthium punctorium). However, the bites of these spiders, unlike the bite of the brown recluse spider, do not produce such severe symptoms.

First aid for a bite

If you are bitten, you must first of all remain calm and call a doctor. Then it is necessary to slow down the spread of poison from the bite site in any way. To do this, you need to apply ice to the bite site. The affected limb should be immobilized and elevated. Antiseptics should be used to disinfect the wound, and aloe juice can be used to reduce pain. If possible, it is worth catching the spider in a clean and secure container - this is necessary for an expert to identify the spider.

There are many treatment options for the effects of a bite, with varying degrees of effectiveness: hyperbaric oxygen therapy, dapsone, antihistamines (for example, cyproheptadine), antibiotics, dextran, glucocorticoids, vasodilators, heparin, nitroglycerin, electric shock, curettage, surgical intervention and an antidote. None of these options have been subjected to controlled trials to determine effectiveness. In most cases, the consequences of bites are cured without any medical intervention.

Precautionary measures

To avoid a spider bite you should:

• thoroughly shake out clothes and shoes before using them;
• check bedding and toilet before use;
• wear gloves when carrying firewood, timber and stones (you should check the gloves themselves before doing this);
• remove boxes from under beds; move the beds themselves away from the walls;
• be careful with boxes - spiders often hide in them;

To limit spider access to your home, you should:

• install a protective screen on windows and doors;
• install door sweeps;
• seal cracks and crevices through which spiders can enter the house;
• install a yellow or sodium gas-discharge lamp on the outside of the house - such lamps do not attract insects that the spider feeds on;
• seal the edges of cardboard boxes to prevent spiders from getting into them;
• use sealed plastic containers for storing things in the garage, basement and attic;

Sanitation:

• promptly get rid of garbage, old boxes and clothes, piles of stones and other unnecessary things;
• clean out the toilet, basement, garage, attic and outbuildings;
• do not stack timber in front of the house;
• prevent the presence of dead insects in the house that the spider feeds on;

Other measures:

• use duct tape to catch spiders;
• thoroughly dust and vacuum the premises to remove spiders, cobwebs and spider eggs (the contents of the dust container should be thrown into trash container outside the home);
• to kill individuals, use a rolled-up newspaper or