A spider is a representative of the animal world of the class of arachnids such as arthropods. The spider order includes 37 superfamilies, 112 families and 4057 genera. Species of spiders differ from each other in size, length of legs, shape and size of chelicerae, degree of toxicity, and appearance. Today there are more than 46 thousand species of spiders, but no one knows the exact number. There are still little-studied places on our planet, and besides, spiders are perfectly camouflaged.
Spiders are obligate predators that eat insects or various small prey that they catch on their own. Moreover, a feature of their structure is the absence of teeth. To eat prey, they have to use their poison, which immobilizes the victim and dissolves its flesh, making it a kind of liquid. Almost all spiders are poisonous, but few pose a danger to humans.
The habitat of spiders is very extensive, they are distributed everywhere. Conventionally, they can be divided into those living in burrows, on the surface of the ground, under bushes or among grass, and those living in trees.
From the following projects we will learn how and what spiders eat, and we will study the structure of the web.
Nutrition
As mentioned above, the main dish of spiders is insects. But the eating process itself is of greater interest, because digestion occurs outside the intestines. The meal can take from 1 to 3 hours.
By piercing the caught prey with chelicerae, the spider injects digestive juice into it in portions, which is produced by the labial glands and liver. It dissolves all soft tissue, leaving hair, bones and chitinous cover. These same chelicerae cause damage, as a result of which the ready-to-use “cocktail” comes out. Like the movements of a cat's tongue, the spider eats it with the help of the muscular rostrum, and then repeats the actions, turning the victim on the other side.
Origin of the species and description
Photo: Yellow Spider
Arachnids arose more than 400 million years ago - among the highly organized organisms that still live on our planet, they are one of the oldest. However, there are almost no relict species of spiders, that is, those that would have lived on Earth many millions of years ago and have remained the same to this day.
They change quickly, and some species are replaced by others, more adapted to changing conditions - this is one of the secrets of their high survivability. And in those ancient times, it was the arachnids that were the first to get to land - the rest followed suit.
How do spiders weave webs?
The web is the most valuable material of arachnids, because with its help they hunt, move, protect themselves, reproduce, weave nests and much more. The arachnoid glands are located in the lower part of the abdomen, and, if necessary, produce a liquid secretion. Coming out through special channels - arachnoid warts, it hardens and turns into a thread, the stickiness and strength of which is determined by the nervous system.
Additional Information! The web of the Brazilian tarantula is so strong that it is used by fishermen to create nets and catch fish.
The shape and size of the web may vary depending on the species, but they are always woven at night, since at this time the conditions are most comfortable. To attach the thread, the spider touches the support with its warts and then pulls it in the desired direction. Moreover, he himself does not stick to it thanks to the fibers on his paws.
Wolf spider: appearance
The size of the spider usually varies between 10-35 mm. The color is predominantly dark, brown, gray or black. Light-colored individuals are noticeably less common. There may be streaks. The coloring of a wolf spider directly depends on its habitat, since the spider protects itself from predators by merging with its surrounding habitat. If you are looking for more wolf spider photos, you can find them below in this article.
Most species have 8 eyes, which are arranged in three rows: the first row (lower) consists of four small eyes, the second (middle) - of two large ones, and the third row (upper) - of two eyes located on the sides and slightly above from middle eyes.
Sexual dimorphism is quite developed. You can distinguish a male from a female by the following characteristics:
- males are noticeably smaller;
- females have a lighter and brighter color;
- The forelimbs of males are more developed.
Safe
The word “safe” means that their bite has not yet caused death. However, it can be painful, cause allergic reactions and be accompanied by swelling, since most spiders still contain poison, although not very toxic.
For people suffering from arachnophobia, their appearance is especially dangerous. Thus, the tarantula grows up to 27 cm in length, has an eerie palette and thick hair, but despite this, exotic lovers see it as an excellent pet.
House spider
From the name it is clear that this species lives near people - in gardens, rotten trees, houses, apartments, warehouses and other premises. Its size is 1-2 cm, and its color is different shades of brown. Rarely does anyone manage to see a web, since it is only several times larger than the individual and is located in dark, secluded places.
This representative feeds on insects and, thanks to its powerful paws, often catches them with lightning-fast attacks. For them, a poisonous bite is fatal, but a person will only feel pain for a couple of hours, so it is absolutely safe. There is a sign that the spider settles in the apartment where peace, tranquility and love reign, so it is only scary in appearance.
South Russian tarantula (mizgir)
It lives in deserts, forest-steppe zones and in places where there is little moisture, and lives most of the time in its burrow. Representatives can grow up to 3 cm, and in appearance and structure they are similar to other tarantulas. The diet consists of insects, but if there is a shortage of food, it may include larger targets - frogs, mice, and other spiders.
Mizgir is also considered safe for people and pets, however, its poison does not cause the most pleasant sensations. The bite site may hurt for 1 to 3 days, while it swells and turns yellow for several months. Often the victim's temperature rises and vomits.
Horse
The dimensions of the jumping spider often do not exceed 10 mm. According to the description, this is a small, nimble spider that can be found anywhere. Due to its tiny body, it eats exclusively insects, and avoids humans even if protected, since it is unable to bite through the skin. “Horses” received this nickname due to their powerful jumps of up to 20 cm.
Their limbs have a special structure and can expand or contract simultaneously with the pressure inside the body. The 8 eyes located around their heads help them calculate the trajectory and distance to the target, and jumps are always made with a safety thread. They can be of different colors - white, blue, yellow, black, because the family has about 5,000 species.
Additional Information! There is a flower spider that belongs to the sidewalker family. You can find it in the flower of some plant, and it got its name for its incredible ability to move sideways.
Argiope Brünnich garden
Despite such a complex name, everyone has seen this spider, because it has a specific color on its back and is somewhat reminiscent of a wasp. This representative belongs to the orb weaver breed, so it is often found sitting on a large round web with its limbs arranged in the shape of the letter X.
Argiope's list of enemies includes everything that falls into the web, even the human hand. There have already been similar cases, but since its poison is weak, no deaths have been recorded. The reproduction of these representatives is much more interesting. Immediately after mating, the female eats the male, and she dies as soon as she lays eggs in cocoons. Thus, the offspring obviously remain without parents and develop independently.
Reasons for the appearance of spiders in an apartment or house
Spiders often live in the forest and on the street, because this is where they can find the main source of their food. Only some species can be classified as synatropic, that is, living close to people. Staying in a human home is unnatural for an arachnid, but these places can also become an attractive place for them to live.
Among the main reasons for proximity can only be the abundance of food, that is, the presence of insects in your home that will become tasty prey for the eight-legged predator.
Additionally, related factors are taken into account:
- comfortable microclimate. Warmth, optimal air humidity and the absence of strong winds that destroy the web. Spiders spend quite a lot of energy and time restoring traps for hunting, but in the house such spider webs last as long as possible if they are not disturbed during regular cleaning;
- factor of chance. That is, arachnids can settle next to a person unintentionally, but we literally bring them on our own;
- in spring and summer they crawl inside through window or doorways, and in autumn they look for secluded warm crevices to escape the cold.
Some representatives appear in the house as pets. Special aquariums are set up for them and their nutrition is carefully thought out.
Routes of entry into human habitation
Common routes of entry into the home include:
- through open window or doorways;
- on the clothes of household members or on the fur of an animal;
- with fruit crops from a dacha or market;
- on plants cut in the field or garden;
- from the attic;
- through sewer lines or from the basement.
At the same time, having made their way into the house, they will be in search of the most comfortable corner for a satisfying and quiet life. The spider prefers an environment without unnecessary worries with an abundance of potential food, but they will be able to settle even in the house. To identify the reason for the presence of arachnids in the house, first of all you need to assess the cleanliness and condition of the house.
In rooms where they are often cleaned, paying attention to the most hidden corners, these creatures hardly get along, since their traps are constantly broken, and insects are not found in constant cleanliness.
Why do spiders prefer to live in houses and apartments?
Ideal living conditions are dark, damp rooms. Temperatures are cool and there are also insects or other small spiders present that would be potential food for a predator. Basement or attic floors are more suitable for this description, but sometimes spiders can also live in living rooms.
To understand why they chose this or that corner, it is important to evaluate your home as a whole:
- humidity in the room. To eliminate this factor, it is necessary to carefully check the sewer channels and the serviceability of plumbing equipment. Leaky faucets and puddles are ideal habitats for arachnids;
- Unsanitary conditions and dirt are common causes of insects. And where there are insects, there will be predators, placing their traps everywhere - cobwebs. If you constantly remove them, the spiders simply will not have time to weave new ones, which means they will not be able to feed and will leave.
Initially, all spiders live only in the wild, but in a person’s home there are much fewer dangers awaiting them. In addition, living conditions are much more comfortable in terms of temperature, lack of strong wind, rain and other factors.
Poisonous spiders
Arachnids are considered poisonous, whose venom can harm the body of humans or large animals. Their number may include representatives who have not had a single human death, but at the same time they are potentially dangerous.
Cross
Crossworts belong to a variety of orb weavers and there are about 600 species. Some of them are found in the CIS countries and are comparable in toxicity to harmless spiders. But the consequences of a bite can be more disastrous, with the manifestation of tissue necrosis.
The size of the crosses ranges from 2 to 4 cm, and the color and pattern depend on the type. But there is one feature common to most representatives - a large and round abdomen. For their own safety, they hide during the day and hunt at night, while feeling hungry very often.
Additional Information! Orb weavers' webs often catch prey that they are unwilling or unable to handle. In this case, the hunter independently frees and releases the victim.
Tramp
One of the most dangerous arthropods of the “runners” family, there are only 8 representatives in their order. The most famous is the Brazilian wandering spider, which in 2010 was recognized as the record holder for toxicity. They do not weave webs, do not build permanent shelters, and at the same time they are wary of people.
This arachnid loves the tropics and lives in Brazil, Mexico, Australia and other places with a similar climate. It reaches 10 cm in size, so it can easily eat not only ticks or insects, but also rodents and birds, killing them with a strong neurotoxic poison. It hunts only in direct line of sight, camouflaging itself on the ground - see photo below.
Among the “vagrants” there is also a safe species, found in Russia, in particular, the Urals, Siberia, and the Volga region. It is somewhat similar to a large house spider and can also live near people. Its venom does not contain a powerful neurotoxin, since the latter is produced only in tropical climates favorable to them.
Folk signs - if there is a spider in the house
It has long been believed that the presence of cobwebs in the house will help cleanse it of negative vibrations and energy, and prevent the development of diseases. This is why spiders were not killed before, but were simply caught and taken out into the street. Over time, people have tried to interpret the presence of a spider in the house in new ways.
- So, if these arthropods were infested in the apartment, then success awaited the owners, including an increase in money. The same sign applied to the person on whom the spider was found.
- If the spider descends down the thin web, then news or a meeting with guests awaits the person who sees it, and if the spider climbs upward, the atmosphere will remain stable.
- Meeting a spider at night promises additional income, but if the spider runs into a hole, you should expect unpleasant events.
- A morning meeting predicts sad news, and an afternoon meeting predicts joy.
- If you see a spider on you that is hiding or even asleep, then soon you will find an expensive new thing and a significant improvement in your financial situation.
Deadly poisonous spiders
Among the many arthropods, there are those that you should not approach. The danger to humans is not the animal itself, but the injected poison and, most importantly, its quantity. This is why some people easily tolerate the bite, while others experience complications, even death.
Brown recluse spider
Along with the Karakurts, the brown hermit is considered one of the most poisonous arachnids. Its bite causes necrosis of the skin and tissue, and with a large dose of poison it can lead to death with a 10% probability. The main danger lies in its inconspicuous appearance and small size - no more than 4 cm. The color is dark or light brown, depending on age and gender - see the picture below.
South America is considered the homeland of this species, but it also lives in Australia and Africa. It prefers to rest during the day, as it does not like sunlight, and at night it hunts small insects. What is surprising is that a hermit can exist for a long time without food. In addition, it is long-lived (up to 5 years) and reproduces quickly without subsequently eating its partner. Several matings may occur per year.
Is it necessary to fight spiders in the house?
To summarize, we can conclude that most spiders are safe for humans and meeting them sometimes even promises something good, if you believe the signs. However, being around spiders is not always pleasant: the web accumulates dust, and sometimes you can even see the remains of insects. Moreover, touching the web is also unpleasant. However, negative feelings alone are not enough. The web is harmful if household members suffer from allergies, and the arthropods themselves can cause an exacerbation of pathological arachnophobia . In addition, spiders, as mentioned earlier, are a sign of unsanitary conditions and a signal to the owners about the need for general cleaning
Danger to humans
As mentioned above, the substance injected by spiders causes the greatest harm to the body. Their poison glands produce 2 types of poison:
- neurotoxic - affects the nervous system, muscles, heart and internal organs;
- necrotic - causes cell death.
In order to cause serious harm to the body, an impressive portion of poison and a weakened immune system are required. With this combination of circumstances, paralysis may occur, the heart rate may become erratic and the limbs may go numb.
Natural enemies of spiders
Considering that arachnids hunt each other, they are considered their own enemies. Frogs, birds, lizards, snakes, wasps, colonies of ants, and various rodents also like to eat them. Moreover, in some countries their main enemy is considered to be humans! So, for Indians, Australians, and Chinese, arthropods are a local delicacy.
Spiders are very specific animals with an interesting lifestyle. Their livelihoods are based on cruel laws, where the strongest survive and sacrifice themselves for the sake of their offspring. This miracle of nature is not a parasite and, despite its poisonous status, is absolutely harmless, because it attacks only in case of self-defense.
The web is needed for insurance
Jumping spiders use web threads to attack. They attach a safety thread to an object and jump onto the intended victim. The South Russian tarantula, leaving its hole, pulls behind it a barely noticeable cobweb thread, along which it will always find the entrance to the abandoned shelter. If the insurance breaks, the tarantula is unable to find its hole and goes in search of a new one. Jumping spiders spend the night on web threads attached to the substrate. This is a kind of insurance against predators.
The main task of the web is to catch prey.
