Spider with a white cross on its back. Should you be afraid of the cross spider, its appearance, bites and venom? Composition and nutritional standards

Millions of different spiders live in nature, killing entire armies of insects that are dangerous both to humans and to their homes.

And if not for these arthropods, the number of mosquitoes, moths, aphids and other insects would be much greater, which would cause great discomfort to people and animals.

What it looks like: description, internal and external body structure

One of the most common representatives of the orb-web spider family is the cross spider, which has more than 1,000 species. Let's consider the most prominent representatives of this family, which are the main characteristics of the body structure.

Common crossweed (Araneus diadematus)

This type of cross spider is a small spider.

External characteristics he has the following:

• the body of an adult male reaches a maximum of 1.1 cm, females are larger, specimens up to 4.0 cm can be found;
• the body cover consists of a durable shell of a yellow-brown hue, which changes during the molting period;
• wondering how many legs there are ordinary cross, you need to know that the spider has 8 legs, each of which plays its own role in the life of the arthropod;
• sense organs are well developed. The spider has a good sense of smell and taste, thanks to the hairs that cover its entire body, it can easily detect even the slightest vibration or vibration;
• four pairs of eyes, each facing in different directions, create a broad horizon.

Important! Despite a large number of eyes, arthropods of this species are myopic. They can only see shadows and the outlines of large objects.

Angular (Araneus angulatus)

Another species of cross spider, which is included in the Red Book in many countries.
External differences represented by the following indicators:

• females reach small sizes, a maximum of 1.8 cm, but they are still larger than the male, whose length is only 1.2 cm;
• they do not have a cross, instead there are 2 small humps that are located in the abdominal area;
• the whole body is dotted with light-colored hairs;
• the oral apparatus is located on the cephalothorax;
• eyes number 8;
• There are 4 pairs of legs on the body.

In general, the body parts and respiratory organs are no different from other representatives.

Marbled (Araneus marmoreus)

This type of spider has its own external differences:

• has significant sexual dimorphism. Females grow much larger than males. Their length is up to 18 mm, spiders grow up to 8 mm;
• these arthropods are endowed with a wide range of colors and patterns. However, the most common one is the orange belly and black pattern. It is this variation that gives the species its name.

Where does he live and how long does he live?

Habitat: damp and damp areas. The greatest likelihood of encountering it can occur in places where a large number of trees grow, where they stretch their webs, as well as along the banks of reservoirs and even in the attics of various buildings.

Did you know? 2.5 billion years ago, the first spiders appeared on Earth, which gave birth to more than 30 thousand species of spiders that live almost everywhere today.

In Russia former countries The CIS, including Ukraine, is home to more than 30 species of spiders. This species of arthropod is a hermit predator, and main feature his behavior is an extremely negative attitude towards others like himself. At night, these arthropods weave their hunting webs, and during daylight hours they hunt their victims.

What does it eat?

The main thing in the spider's diet are small insects. During the day, the female absorbs food in an amount equal to her weight. When an inedible insect gets into the web, the spider gets rid of it by breaking the threads.
He also tries to avoid flies and wasps, which can lay eggs on other animals. Hunting occurs in two ways: in the center of the web or from a nearby shelter.

The predator is not able to immediately consume food, so it quickly injects aggressive juice into the caught prey, places the prey in a cocoon and waits for the victim’s insides to turn into a nutrient solution. This process takes approximately 1 hour, after which the spider sucks out the prey, leaving the cocoon behind.

Web of the cross spider

All the webs that spiders weave are no different from one another, since the ability to weave a web is inherent in these predators at the genetic level. Only females are engaged in weaving such beautiful, intricate patterns.

Did you know? In microbiology, spider webs are used as the thinnest optical fiber to detect the composition of air in the atmosphere.

The web has strictly 39 radii and 1245 points of their attachment to the spiral, which, in turn, consists of 35 turns. The threads that make up the web are light, but at the same time they are very strong - they are used by tropical residents to weave nets and fishing gear. In addition, the threads are very elastic.
In the process of arranging her creation, the female uses two types of threads. The base and radii are woven from dry fibers of a durable structure without a sticky coating and stretched between the branches.

Then the spider begins to weave threads, which are located from the center to the edges, and a spiral thread, which will be the basis for the catching spiral. After the work has been done, the spider lays a web with an adhesive base from the center of her creation.

The spiders themselves move only along dry threads, so they do not get stuck on their fishing nets. It takes the spider approximately one hour to weave the entire web.

Poisonous or not

The venom of the brown cross contains heat-labile hemolysin, which has a negative effect on blood cells.

However, its dose is so small that it can only harm small animals. A spider bite is not dangerous for humans, but minor discomfort may occur if you are allergic to animal bites.
At the site of the bite, minor pain and itching occurs quickly. To quickly relieve these symptoms, you need to wash the affected area of ​​skin with soap and apply something cold, ice if possible, then apply ointment to relieve inflammation.

Important! The spider never attacks first - a bite is possible upon accidental contact.

Reproduction and offspring

The mating season for spiders takes place in August. During courtship, the male, in order not to become a victim, carefully approaches the edge of the web, pulls the threads with his paws and waits until the female responds in kind. Then mating occurs, after which the male dies.

Immediately after mating, the female begins to weave a cocoon into which the eggs will later be placed. The cocoon will stay with her for a while, and then she will hide it in a secluded place.

In the fall, the spider lays an average of 500 eggs in the cocoon, which are completely preserved in it until spring. After hatching, many small spiders die as a result of high competition and attacks from relatives.
They are faced with an acute question of survival, and for this they need to leave the maternal cocoon as quickly as possible. The legs of spiders are small and weak. Because of this, they move on the web, gliding under the influence of the wind like on a magic carpet.

When the wind subsides, the web falls to the ground, and the spider leaves it, starting new life. If the site turns out to be successful, then with the help of his nets he will be able to catch up to 400 insects throughout the day. By the beginning of summer, spiders are already capable of mating, and by this time the spider that gave them life dies.

Did you know? With the help of a web, the cross can cover about 400 km.

As can be seen from all of the above, the opinion of many that all spiders with crosses on their bodies and villi are dangerous to people is wrong. However, despite this, you should not tempt fate and try to pet or pick up this arthropod.

The crusader spider differs from its fellow spiders in its impressive size. The length of females is more than 2 cm, while the male is half that size. The larger size of females is necessary to kill the male after mating, and also allows them to safely carry a large cocoon with small spiders on themselves.

How many legs does a cross spider have? Like all arachnids, the insect has four pairs of legs, which are especially sensitive due to the three claws located at the very tips. With them he catches the victim.

On the back, the spider is awarded a cross of small circles of light or light brown color, located on the upper part of the abdomen, which is why it got its name. A black spider with a white cross on its back lives in shaded places - forests, groves, and various thickets. If there is enough sun and light, then the insect is lighter in color, and its chitinous coating fades from bright rays. In the lower part of the abdomen there are arachnoid glands that are capable of producing various webs. For hunting - thin and sticky, and for the maturation of small spiders and cocoons - soft and silky.

The body is covered with hairs that function as a tactile organ. The color of the abdomen of the cross spider also depends on the habitat. Ordinary representative Arachnids of the araneomorphic genus have two pairs of dark-colored eyes.

Their vision is poor - blurry objects and outlines. Crusader spiders react to movements around them.

Cross spiders weave webs quite often - one every 2-3 days, as other insects, animals and weather destroy it. It prefers insects, but mainly feeds on flies, aphids, mosquitoes, grasshoppers and others. Active at night. During the day he rests, but keeps a signal thread under his foot. From trapping nets it throws out victims that are too large or unfit for food. They are distinguished by their particular gluttony - in a day the cross eats its own weight in insects.

Symptoms of cross bites

He never attacks a person. Bites occur due to the latter's interference in the life of the insect.
A spider bite is accompanied by the following symptoms:

1. Itching. The bite site itches unbearably due to neurotoxins and hemotoxins contained in the venom of the cross.
2. Hyperemia of the skin.
3. Slight swelling, as with.
4. Pain is more common in children or people with hypersensitivity.

The cross spider is poisonous only to small mammals - mice, rabbits, small dogs and young animals. For an adult healthy person the bite of a cross spider is not dangerous. It is necessary to regularly examine pets in order to start or spider in time.

But if a person is prone to various allergic reactions or a child is injured, then an insect bite will cause mild symptoms:

• weakness;
• chills;
• headache;
• increase in body temperature;
• swelling and hardening at the site of edema.

The hemotoxin contained in the poison causes the development of hematoma and subcutaneous hemorrhage.

First aid for a bite

First aid for a spider bite involves simple steps:

1. Wash the bite area with cool water and soap.
2. Treat with antiseptic solution and alcohol.
3. Apply cold to reduce itching and swelling.
4. Take an antihistamine to prevent the development of allergic symptoms.
5. For headaches, take an antispasmodic (nosh-pa, drotaverine, etc.).
6. It is advisable to use anti-inflammatory or antihistamine ointments and creams: Bepanten, Fenistil, Soventol, Baneocin and others.

The cross spider contains venom that is rich in eperotoxin, neurotoxin and hemotoxin. All these substances are eliminated from the body within one to two days. If the bitten person does not feel better after this time, then seek medical help, as with.

Prevention

When relaxing in nature, avoid beautiful wheel-shaped webs and do not pick them up. When sleeping in a tent, you need to close it carefully. If you find a web in your dacha or at home, you should carefully remove it with a long stick and throw the spider outside using a newspaper or a jar. Don't touch it with your hands. The insect should not be killed - it is an amazing specimen that brings benefits to humanity.

Spiders are distributed throughout to the globe everywhere, only they do not live at the North Pole. There are more than 30 thousand species of these arthropods in the world, more than 2 thousand species are cross spiders. On the territory of Russia there are no more than 2 dozen species of crosses. Like all living creatures, spiders protect themselves from danger by using their poisonous teeth. Sometimes people become victims of spiders, and for some, a spider bite results in serious complications. What kind of insect is the cross spider, and is it dangerous for humans (see)?

You can meet the cross spider both in nature and in a person’s home. The spider chooses dark, damp shelters, where it is easiest for him to hide. Arthropods lead predominantly night look life, during the day it hides not far from its web. As soon as prey gets into the web, the fishing thread begins to vibrate, and the spider immediately rushes towards its victim.

How to recognize a cross

To distinguish the bite of this insect from others, you need to know what a cross spider looks like. The spider owes its name to the cross-shaped mark located at the top of its abdomen. The arthropod has a cephalothorax and a round belly of a dark brown color, 8 limbs that are highly sensitive and 8 eyes. The spider's eyes are located on different sides, which allows the insect to see everything that happens around it. Female crosses have a body length of up to 3 cm, males are much smaller and have a length of about 1 cm.

Arthropods feed on small insects (mosquitoes, midges, flies and aphids), which, when caught in the spider’s web, cause vibration of the threads. The spider, with the help of its sensitive legs, immediately understands that prey has fallen into the web. The arthropod then kills the captured insect using its poisonous teeth. The cross sometimes immediately eats its victim, but if it is full, it entangles it in a web and hides it in a secluded place.

To reproduce, the male spider selects a female with a web and attaches himself to her trapping net on the side. Then he begins to send signals to the female so that she notices him. After mating games the male usually dies, and the fertilized female begins to weave a cocoon in order to subsequently lay eggs in it. For some time, the mother carries a cocoon with eggs on her belly until she finds a suitable secluded place for it. Having chosen such a place, the spider hangs a cocoon there, and after a short time the spiders hatch from the eggs.

Symptoms of a spider bite

Is the cross spider considered poisonous? The arthropod does not pose a danger to large animals and humans; its toxic substance is only enough to kill mice and rats. However, this does not mean that a spider bite is harmless. A person, as a rule, can suffer from an arthropod attack if he accidentally gets caught in a web. In this case, the spider may attack a person, mistaking him for a victim. Also, for the purpose of self-defense, the cross spider will certainly bite a person if he tries to catch it and pick it up.

At the site of the spider bite, a small white spot appears, which has a diameter of no more than a 5-kopeck coin; the edges of the spot are slightly red. The pain of a cross bite is similar to that of a bee (see). Some people may not notice the skin puncture at all. Swelling appears at the site of the lesion, which, depending on a person’s sensitivity to the spider’s poisonous substance, can be quite impressive in size. For allergy sufferers, the cross spider is considered poisonous (see). Symptoms of a crossworm bite are:

• burning in the affected area;
• weakness of the body;
• redness of the skin;
• pain in the limbs;
• headache;
• heat bodies;
• the skin at the site of the bite hardens.

Attention! Children and people suffering from allergic reactions are most sensitive to the bite of the cross. Allergy sufferers may experience serious complications in the form of severe swelling, difficulty breathing and cardiac dysfunction. If any serious signs occur, the victim should be immediately taken to a medical facility.

First aid for a spider bite

No fatalities have been recorded as a result of the spider's attack, but this does not mean that the victim of an arthropod bite does not need help. In such cases, you must proceed as follows:

1. The bite site should be washed with warm soapy water to wash away microparticles of dirt from the skin and prevent infection from entering the wound.
2. It is recommended to apply a cold compress to the affected area; ice or a bottle of water will do. cold water. Cold will help reduce pain and relieve swelling (see).
3. If there is a pain in the head or a rise in temperature, it is better to give the patient a Paracetamol tablet.
4. If an allergy occurs, the victim should be given an available antihistamine.
5. People suffering from allergies, after being bitten by a cross, must be provided with complete rest and immobilization. Before the doctor arrives, the sick person is vigorously given warm liquid.
6. The bite site should not be cauterized with hot objects, much less cut into the wound. These actions threaten the penetration of pathogenic bacteria into the affected surface of the skin and the development of purulent inflammation. Also, the wound should never be scratched.

Important! If a spider attacks a child, you must seek medical help immediately, as the spider's venom is toxic to small children.

Prevention of cross bites

A spider attack can be prevented by following simple rules:

• when going overnight into nature, you must use special insect repellents;
• the entrance to the tent should be covered very tightly;
• before going to bed, you need to carefully check your bedding for insects;
• After waking up, you should check your personal belongings (clothes and shoes). Spiders can easily hide in a person’s belongings;
• It is better to choose clothes for hiking in nature with long sleeves and trouser legs;
• Having noticed the web of an arthropod, you need to try not to touch it. If there is a web, its owner is always nearby;
• do not go into abandoned dark buildings such as sheds and barns; spiders love to settle in such places. In the dark, where the cross spider lives, you may not notice the woven web and fall right into it with your face. In such a situation, the bite of the cross will be inevitable;
• Children need to be explained that they should not tease or catch arthropods.

The spider has an excellent appetite; in one day it can eat as much food as it weighs. If a large or poisonous insect, which is a threat to the life of an arthropod, the spider tries to get rid of it as quickly as possible. To do this, it simply breaks off its web, and the insect, unsuitable for food, falls.

The threads for weaving the web are located in special warts located at the bottom of the spider's abdomen. When the spider shoots threads, under the influence of oxygen they harden and become strong. To weave one catching net, a cross stitch requires about 20 m of thread.

Since ancient times, people have used spider webs as an antibacterial agent, so if you are bitten by a spider, you can apply its own web to the wound.

Conclusion

Cross spiders do not pose a potential danger to human life, but this does not mean that you can try to catch the spider. Cross bites are quite painful, especially for young children. For people prone to allergies, they can cause serious consequences for good health.

The cross spider catches its prey using a web. The spinning apparatus of spiders consists of external formations - arachnoid warts - and internal organs - arachnoid glands. Three pairs of arachnoid warts are located at the posterior end of the abdomen. Each such wart is pierced at the end with hundreds of tiny holes. From each hole flows a drop of sticky liquid, which, when the spider moves, is pulled out into the thinnest thread. These threads merge into one and quickly thicken in the air. The result is a thin but strong thread. This sticky liquid is secreted by numerous arachnoid glands located in the back of the abdomen. Their ducts open on arachnoid warts.

To form its trapping net, the cross spider first attaches a thread in several convenient places, forming a frame for the net in the form of an irregular polygon. Then it moves to the middle of the upper thread and, going down from there, draws a strong vertical thread. Then, from the middle of this thread, as if from the center, the spider draws the threads in all directions, like the spokes of a wheel. This is the basis of the entire web. The spider then begins to draw circular threads from the center, attaching them to each radial thread with a drop of adhesive. In the middle of the web, where the spider itself then sits, the circular threads are dry. Other threads are covered with droplets of a very sticky liquid and are therefore always sticky. There are over 100,000 such droplet knots in this network. Insects that fly onto the net stick to them with their wings and paws. The spider itself either hangs head down in the center of the web, or hides to the side under a leaf. In this case, he extends a strong signal thread towards himself from the center of the web.

When a housefly gets into the net, the spider, sensing the trembling of the signal thread, rushes out of its ambush. By piercing its claws with poison, the spider kills the victim and secretes digestive juices into its body. After this, he entangles the fly or other insect with a web and leaves it for a while.

Under the influence of secreted digestive juices internal organs Spider victims are quickly digested. After some time, the spider returns to the victim and sucks everything out of it nutrients. All that remains of the insect in the web is an empty chitinous covering.

Making a fishing net is a series of interconnected unconscious actions. The ability to perform such actions is instinctive and is inherited. This can be easily verified by observing the behavior of young spiders. When they emerge from their eggs, no one teaches them how to make a catching net, but the spiders immediately weave a web correctly.

Body structure of a cross spider

The cross spider is a common inhabitant of our forests. It is also easy to find it in your yard or even in your home. This spider, which has a yellowish-brown or almost black color, is very easy to recognize by the white cross-shaped spot on the dorsal side of the body. Thanks to this feature, it is called a cross. Its coloring has a protective value; it makes it invisible in the twilight among dense bushes, between tree trunks.

In some structural features, the cross spider resembles crayfish, but at the same time it differs from it in a number of features associated with a different way of life. The class of arachnids changed under the influence of the transition from an aquatic to a terrestrial lifestyle. Like crayfish, the body of the class of arachnids (cross spider) consists of two sections: the cephalothorax and abdomen. But his abdomen is highly swollen and not dissected. Unlike crustaceans, there are no antennae on the head of the cross spider. The cross spider, like the tick, does not have compound eyes. On the upper side of the head there are eight simple ocelli, and on the lower side, around the mouth, there are two pairs of jaws. Spiders are predatory animals. They feed mainly on insects. The spider uses its front pair of jaws to kill its prey. There are poison glands at the base of the jaws. When the claws that end the jaws penetrate the prey, the poison flows into the wound and kills the victim.

The spider uses its second pair of jaws to chew its prey. Behind the jaws are four pairs of long walking legs. Like crayfish, the spider's legs consist of separate segments. Each leg ends in jagged claws, so the spider can run across its web without becoming entangled in it. The claws also help the spider weave its web. Unlike the crayfish, the spider brooch has no limbs.

Virulence

The cross spider is poisonous, but not fatal to humans. As a rule, crosses are not able to bite through human skin, but if this does happen, then a red spot forms at the site of the bite and slight tissue necrosis from the action of the poison.

Treatment for a bite

Apply cold compresses to the site of the spider bite.

The cross spider, also known as the crusader, araneus, belongs to the family Araneidae. There are 621 species in the genus of crosses. Spiders live all over the world and are common in our area. You can meet a predator everywhere - in the forest, field, edge, park, vegetable garden, yard, outbuildings. Often crawls into the house through cracks in the wall, open windows, doors.

Description and photo of the cross spider

The body size of females is from 20 to 40 mm, that of males is 10 mm. Consists of a round convex abdomen, cephalothorax. The body is covered with a durable shell, the legs are covered with villi. The crusader spider has 10 limbs, of which 4 pairs are walking legs. The front ones perform the functions of claws - they capture the prey and hold it while feeding. The paws are symmetrical to the size of the body. The structure does not differ from the typical one. The cephalothorax is connected to the abdomen by a thin bridge.

How many eyes does a cross spider have - 8. Placed on the front of the head. 6 in the center, 2 large on the sides. This provides a broad outlook, but does not provide good vision.

Interesting!

The spider is myopic, sees everything in general outline– movement, shadow, silhouette. The organs of smell and touch help the cross to navigate in space. Located on the legs. Finding itself in an unfamiliar place, the spider carefully feels the space initially with its paws, and then moves.

What a crusader looks like depends on the species. The body structure is the same, but the color is different.

• The meadow crossweed lives in places with moist air, warm climate, dim light. Painted in brown, yellow, red tones. On the belly on the upper side there are white spots in the shape of a cross. Thanks to this identification mark all araneus species are called crossworts. Meadow predator on the grass, hunts small insects.
• The forest cross differs from the garden and meadow in its darker color. The body is dark brown with white stripes. The characteristic white or brown sign of the cross is clearly visible on the abdomen. The paws are long. The largest cross in Russia. The size together with the leg span reaches 4 cm.
• The Far Eastern cross is different large sizes. Habitats: forest, field, meadow. The color is brown with different shades. The cross on the abdomen is white or yellowish. It weaves the largest web, which reaches 2 m in diameter. Even frogs, toads, and snakes can become entangled in strong webs.
• Orange or yellow spider with a cross on his back - an ordinary crusader, living in shady places in the forest, field, meadow, garden. Araneus angulatus is a rare species listed in the Red Book. Body size is about 18 mm.
• The predator with a red cross on its back is a type of meadow cross. Bright spots scare away enemies, but do not mean that this representative of the genus is more poisonous.
• A black spider with a white cross on its back is a crusader that lives near swamps, in the forest, in fields, and rarely approaches a person’s house. Outwardly it resembles a tegenaria.

What a cross spider looks like depends on the species, but what distinguishes them from other representatives of arachnids is a characteristic pattern on the back in the shape of a cross. This is where the name comes from.

Where does he live?

The species is distributed throughout Europe, some varieties live in North America. Favorable living conditions are high humidity, high temperature, lack of direct sun rays. Ideal habitats are coniferous forest, swamps, edges, hedges. Less often they settle in meadows, fields, gardens, vegetable gardens, outbuildings, and residential buildings. There are about 30 species of crosses living in Russia and the CIS countries.

On a note!

Once in a person’s house, the spider chooses places away from noise and light. Occupies corners at the top of the room, below behind the furniture. Weaves a web. It feeds on “domestic” insects – , . To get rid of a spider with a cross on its back, you need to remove its web, throw it outside, and poison the “living creatures.”

Lifestyle

Common cross spider – resident wildlife, but under certain circumstances. Leads a nocturnal lifestyle, during the day it sits motionless in a shelter or on a web of cobwebs. He weaves it at night. It makes a shelter out of leaves and builds trapping nets between the branches.

Experts managed to find out how the female cross weaves a web. The network consists of 39 different radii, which expand as they move away from the center, 35 spiral turns, 1245 points of contact of threads. The radius of the web of the large Far Eastern cross reaches up to 2 m.

Interesting!

At night the female weaves a net, and during the day it catches prey. The spider eliminates the damaged areas and forms new coils in their place. Natural enemies There are birds, but with the onset of darkness their activity decreases. The cross can work quietly.

The lifespan of a spider is theoretically 2 years. Under natural conditions it is somewhat shorter. How long does a cross spider live? pet, depends on proper care. Quietly lives up to 2 years.

Nutrition

The main diet consists of insects different sizes. The spider's trapping nets catch flies, wasps, hornets, grasshoppers, locusts, caterpillars, and butterflies. Snakes, frogs, toads, and mice get entangled in large, strong webs.

Internal digestive system absent, liquefaction of food occurs externally. The spider bites the victim, injects poison that paralyzes the muscles and immobilizes the prey. The cross releases saliva into the insect’s body, envelops it in a web, and waits for several minutes. In 5-20 minutes, the insides of the prey turn into a liquid mass, which the predator sucks up.

Reproduction

The mating season begins at the end of summer. The female waits for the male on her web and senses his approach by the vibrations of the web. After fertilization, it spins a cocoon and lays up to 250 eggs inside. He carries it with him and then leaves it in a secluded place. The young animals spend the winter in this state. Spiders are born at the end of April.

The maturation period lasts several months. During this time, the nymphs molt about 5 times, increase in size, and acquire a characteristic color. By the end of summer they become sexually mature. Caterpillars serve as food for the young animals.

On a note!

How adult spiders overwinter - they hide in cracks in walls, utility rooms, forest litter, tree hollows. They become active as air temperatures rise in spring.

Poisonous or not crusader

The poison is toxic to invertebrates and vertebrates. It has an effect on the body of rats, mice, humans, and rabbits. Sheep, horses, Guinea pigs, dogs are resistant to poison. For insects and invertebrates, a crusader attack is fatal. Animals experience temporary deterioration in well-being and external irritation.

The Crusader is not dangerous to humans. When it sees people, the spider tries to hide unnoticed. However, in the event of a threat to own life may bite. There are 2 small spots left on the body. Initially there is pain and burning. The next day, suppuration occurs. In people with weakened immune systems and children, their overall health deteriorates afterward. Weakness, nausea, headache, dizziness, and abdominal discomfort appear. The condition returns to normal in a few days.