Find out what structural features of ticks and spiders indicate their similarities and differences

A rather interesting question is how many legs a spider has. A very large number of people confuse these animals with other arthropods, in particular insects or mites. Therefore, this article will answer not only the question of how many legs a spider has, but will also make a comparison with ticks, since the latter also belong to arachnids.

It is especially important to consider that the ability to distinguish our hero from a tick is also important in practice.
In particular, the latter are carriers of a large number of diseases or simply provoke allergic reactions in the body.
Both the arachnids and the other have eight legs, but they can be distinguished even externally. What to say about internal features related to behavior or other aspects of his life. Well, let's figure out from the very beginning what spiders are in order to figure out how to distinguish them from ticks.

Origin of the species and description

Photo: Mite

The tick is an arachnid animal that feeds on the blood of animals and humans. Nowadays, there are a huge number of varieties of this species, up to 40 thousand.

But two types play a significant epidemiological role:

• taiga tick - its habitat is the Asian and partly European parts of the continents;
• European forest tick - habitat is the European mainland of the planet.

Video: Tick

To this day, scientists have not come to a consensus on where exactly ticks came from and from whom they originated. The main thing is that over a million years of evolution they have practically not changed. The fossil mite is very similar to the modern primitive specimen.

The main hypotheses for the origin of ticks today are the following:

• neotenic origin. Ticks could have originated from chelicerate animals, which were many times larger, but were at an early stage of their development;
• origin from floating larvae of creatures that were unable to move and did not have a central nerve core;
• occurred by truncating the life cycle of an animal that was more specialized.

The latter hypothesis was even directly confirmed. Thus, a chelicerate animal was found with a clutch of hatched eggs. The larvae of these eggs are very reminiscent of ticks, incl. have the same number of legs.

Biological control measures

To date, it is not known for certain about any specific species of insects or spiders whose diet includes specifically pasture varieties of pests. However, there are a number of predator species that are known to attack ticks. These predators include predatory mites, small beetles and spiders.

As for plant protection, several methods and conditions are also noted here, the use of which can reduce the mite population. For example, crops with a high content of clover are at greatest risk. Avoid planting susceptible crops such as canola, lupine, vetch and alfalfa near clover fields or pastures where this plant has an advantage. Also, early and constant treatment of useful crops from weeds, especially broad-leaved ones, will provide protection against the spread of mites to cultivated plants.

What is a pest?

Pests are those living beings that cause harm to other organisms; this has a lot in common with parasitism, but pests do not have to do this, in the broad sense of the word, in order to survive. The term pest is especially relevant for humans. For example, locusts are capable of destroying crops that people have made to support their livelihoods. Capable and destroyed, but could not have done it and in this case would not have died. The caterpillar of the cabbage butterfly prefers cabbage, but burdock leaves would be enough for it to survive.

And one more important comparison of concepts. It would be more correct to say that they treat parasites, but fight pests.

Appearance and features

Photo: What a tick looks like

The size of the tick is small, depending on the type of animal, ranging from 0.1 mm to 0.5 mm. Since ticks are arachnids, they do not have wings. An adult tick has 8 legs, and an individual that has not reached sexual maturity has 6.

On the legs there are claws and suckers, with the help of which the mites are attached to plants. The animal has no eyes, so a well-developed sensory apparatus helps it in orientation. Each type of tick has its own color, habitat and way of life.

Interesting fact: The tick's sensory apparatus, which is located on its limbs, allows it to smell the scent of a victim 10 m away.

The body structure of the tick is leathery. His head and chest are fused, and his head is attached to his body motionlessly. Oribatid mites breathe using special spiracles.

Ticks are quite voracious, but in dangerous situations they can go without food for up to 3 years. By feeding abundantly, ticks increase in weight by more than 100 times.

Interesting fact: It is quite difficult to see a tick with the naked eye. For example, three pincers placed together will correspond in size to a punctuation point.

On average, the tick development cycle lasts from 3 to 5 years. During this long period, ticks allow themselves only 3 meals.

Nymph

Not all types of ticks go through all three stages in their development. Three instars are present in ixodid and argasid ticks. Sarcoptoid and teranichidae pass through the 1st and 3rd instars. Thrombidiform mites pass through the first two instars. Each age has its own name:

The protonymph already has 4 pairs of legs, which still have very few setae. Also at this stage, a genital opening and 2 genital setae with a pair of genital tentacles appear.

In deutonymphs, the number of setae on the tarsi increases. 6 genital setae and 4 genital tentacles appear.

Tritonymph continues to acquire genital tentacles (already 3 pairs) and setae. The number of tactile bristles on the legs and body surface increases. If you look at the images of all three forms, you can see that the anatomy of the third instar nymph is almost no different from the morphology of ticks.

Adult

Adults are microscopic in size. The body length of this mite is 0.2-0.8 mm. The body is oval in shape and divided into gnathosoma and idiosoma. Gnathosoma is

complex of oral parts. The rest of the body is represented by the idiosome. The idiosoma contains four pairs of walking limbs. The color of the body has several variations: it can be from orange-red to dark red, and sometimes cherry color.

The presence of morphological adaptations is characterized by the presence of long dorsal setae and specially arranged pretarsuses of the limbs. Thanks to these adaptations, phytoseiulus is able to slide between spider threads.

Predators are nymphs, deutonymphs, and adults, regardless of gender.

Where do ticks live?

Photo: Klesh in Moscow

Ticks can be found anywhere on the planet. All climatic zones are suitable for their life, regardless of continent, weather conditions and temperature conditions.

The most overgrown place with grass that does not outwardly inspire confidence can be absolutely safe, and vice versa, a well-groomed and landscaped park can be overpopulated with ticks and potentially dangerous.

After all, the presence of benches and trimmed grass does not guarantee the absence of ticks and does not protect against encephalitis. There is a very widespread belief that ticks live on trees and wait for their victims there, rushing at them directly from the branches.

But this is a fairly common myth that has nothing to do with reality. Ticks live in grass and as close to the ground as possible. Tick ​​larvae are found on the grass at a height of 30 centimeters to one meter. The ticks themselves sit on the inner sides of plant leaves next to pedestrian roads and animal paths and cling to anyone who touches this very plant.

According to statistics, a tick usually bites an adult on the lower part of the body: legs, buttocks, groin. But the vast majority of children are bitten in the head and neck area. But, in both cases, there are bites on both the arms and the torso.

What does a tick eat?

Photo: Tick in the forest

Ticks also differ in their feeding methods.

Based on this feature, they can be divided into two groups:

• saprophages;
• predators.

Saprophages eat organic remains. That is why such mites are considered very useful for nature and humanity, since they make a certain contribution to the creation of humus. However, there are saprophagous mites that feed on plant sap. These are parasitic mites. This type of animal causes great harm to agriculture, as it can destroy grain crops.

There are mites that eat exfoliated particles of human skin - the epidermis. These mites are called dust mites or scabies. Barn mites are suitable for feeding on plant residues that decompose, incl. rotting flour and grain.

For the subcutaneous mite, the ideal option is subcutaneous fat, which it takes from human hair follicles, and for the ear mite, the fat from the ear canals. Predatory mites parasitize other animals and plants. Using its legs, a blood-sucking tick attaches itself to its victim, and then purposefully moves to the feeding site.

Interesting fact: A blood-sucking tick can choose its relative, the herbivorous tick, as its victim.

How to protect yourself from parasites

Vaccination against encephalitis and the use of repellents are suggested as preventive measures. When visiting the forest, it is advisable to choose the right clothes. It should hide the arms and legs; it is advisable to have a headdress. The period of parasite activity is late spring and early summer. The second wave begins with a decrease in temperature in August-September. At this time, you should be attentive to yourself and your pets.

Advice. Choose light-colored clothing for hiking; brown ticks are easier to spot on them.

How dangerous are ticks?

In addition to blood-sucking species that spread deadly diseases, there are many ticks that cause trouble. They are a source of irritation and allergies in people and pets. Some are unlikely to cause damage to gardens, fields, and settle on indoor plants. Among the species that exist near humans:

• Gamasidae - parasitize birds and rodents, causing significant damage to poultry farms. Causes feather loss in chickens.
• Scabies is a microscopic parasite that causes an intractable skin disease.
• Ear - settle in the ears of domestic animals - cats and dogs. Cause severe inflammation, itching and scratching. Treatment with acaricidal drugs is required.
• Subcutaneous or demodecos - present in limited quantities on the skin of most people. With pathological spread, they cause itching and redness. Size 0.2 mm.
• Dust or bed - the microscopic inhabitant of house dust provokes allergies with its excrement.
• Arachnoid is a phytophage in the arachnid family, feeding on plant sap. It is a carrier of disease and rot.
• Flour - damages the reserves of granaries, contaminates flour with its waste. Promotes the spread of mold.

Where do mites come from in apartments? They get into homes with dust, on people's clothes, and animal fur. Favorable indoor conditions and an abundance of food lead to their spread.

Features of character and lifestyle

Photo: Tick in Russia

Ticks begin to become active in mid-late spring, namely at the end of April, beginning of May. To awaken them, it is necessary for the earth to warm up to three to five degrees. And this continues until the end of August, beginning of September, until the temperature of the earth drops to the same level. The population and density of ticks directly depends on weather conditions. If the summer was not hot and with a lot of rain, and the winter was snowy and not severe, then next year the tick population and density will increase.

The female tick, after sucking blood at the beginning of summer or late spring, lays eggs from which larvae will appear, but they will bite anyone only the next year. But, the larva or nymph, which sucked blood from the host this year, moves to the next phase of development also this year. After a tick has chosen a victim and attached itself to it, it may take about twelve hours before it begins to suck blood. On the human body, ticks prefer places with hair, as well as places behind the ears, knees and elbows.

Due to the fact that ticks have saliva with an anesthetic effect and anticoagulants in their arsenal, their bite is invisible to the owner. The maximum duration of blood sucking by a tick is fifteen minutes. The life expectancy of ticks also varies depending on the species. Dust mites live from 65 to 80 days, but mites living in the taiga live about four years. And without food, depending on the species, ticks live from one month to three years.

Now you know how dangerous a tick bite is. Let's see how they reproduce in the wild.

Details

Appearance

Spiders do not have as many legs as insects; spiders always have 8 legs, while insects only have 6.

Spiders also have an ability that other insects do not have; they can secrete webs. Apart from spiders, this can only be done by pseudoscorpions, certain types of ticks and centipedes. To produce webs, the spider uses arachnoid warts on its abdomen. In its composition, the web is very similar to silk fiber, which can be secreted by insects, but it has no equal in strength.

Spiders have three pairs of arachnoid warts; they release a thin stream of sticky liquid, and it hardens after 5-6 seconds, while remaining just as sticky. Spiders from the web weave their spider web, and it turns out to be a trap for insects that do not know how to make such lace themselves, and unknowingly fall into it.

There is another difference between spiders and insects. This is the process of nutrition. If you take and look at the Brazilian banana spider and the large mantis, they are similar in some respects. These predators are approximately the same size; the spider has a large paw span. The length of an insect and a spider is about 16 cm. And in terms of food, their preferences are similar, these are insects, lizards, frogs and even small rodents.

They are also similar in the way they hunt. Both the praying mantis and the Brazilian banana spider wait in ambush for their prey, and suddenly jump out and pounce. But they eat caught prey in completely different ways. The praying mantis grabs the food with its tenacious paws and does not release it again until it has completely eaten it. But the spider does not do that; it bites into the body of the caught insect or animal with its poisonous chelicerae. After this bite, the victim may either die immediately or be unable to move. After this, the spider, using its web, entangles the victim and injects gastric juice, which dissolves all the insides of the caught prey. After this, the spider eats slowly, this can even last for several days. The spider makes a special cocoon with its victim, where it is digested. Spiders do this because their mouthparts are not capable of chewing food.

Morphology

According to research by scientists, only some species of spiders have unusual and strange morphological phenomena, when small spiders can eat their mother, but they do this with her consent.

It must be said that no spiders that are deadly to people have been spotted in central Russia. There are very large spiders, but their bites may cause a burning sensation and rarely increase the temperature. However, in most cases, spiders do not attack first. If a situation arises that a spider falls from its web onto a person, then it is better to simply blow it away and not hit it, otherwise it may bite.

As a rule, insects have only two eyes, which have a complex structure, while spiders have more primitive eyes, but there are more of them. Spiders usually have eight or six eyes, in rare cases there are only two. Male spiders have a bulbus on their forelimbs and it is in them that the sperm for fertilizing the female is stored.

There are types of spiders whose males are ready to die in advance after mating with a female; they allow her to eat them, and some fight for their lives and run away.

Among spiders, males often do not live long, unlike females, who need to raise little spiderlings, which is why they live much longer. Also, among spiders, females are usually larger in size, while spiders are smaller. Most female spiders tend to be caring mothers; for babies, they weave a cocoon from a web, and little spiders sit in it. Almost all spiders are predators.

Biological characteristics of the insect

The pasture mite, or clover mite, entomologically belongs to the Bryobia family. These insects have relatively recently been identified as pests of winter crops and pastures in the southern parts of our country. This mite was first reported in the early 1900s, but has only been actively studied and controlled in the last decade, as the insects were identified as pests capable of causing significant damage in crop production.

It is worth noting that control of parasites is complicated by the large number of tick species, as well as their small size and lack of suitable morphological characteristics, which makes identification a rather difficult process.

In Russia, there are at least seven different Bryobia species living among wide expanses of agricultural land and pastures.

Of these seven types, three are the most common. It is against them that a purposeful struggle must be waged.

Notes[edit | edit code]

1. ↑ Arachnids. bigenc.ru. Great Russian Encyclopedia. Access date: June 10, 2022.
2. ↑ Zhang, Z.-Q. "Phylum Athropoda". — In: Zhang, Z.-Q. (Ed.) Animal Biodiversity: An Outline of Higher-level Classification and Survey of Taxonomic Richness (Addenda 2013). (English) // Zootaxa / Zhang, Z.-Q. (Chief Editor & Founder). - Auckland: Magnolia Press, 2013. - Vol. 3703, no. 1. - P. 17-26. — ISBN 978-1-77557-248-0 (paperback) ISBN 978-1-77557-249-7 (online edition). — ISSN 1175-5326.
3. ↑ 1 2 3 4 5 6 7 8 Ruppert E. E., Fox R. S., Barnes R. D. Arthropods // Invertebrate Zoology. Functional and evolutionary aspects = Invertebrate Zoology: A al Evolutionary Approach / trans. from English T. A. Ganf, N. V. Lenzman, E. V. Sabaneeva; edited by A. A. Dobrovolsky and A. I. Granovich. — 7th edition. - M.: Academy, 2008. - T. 3. - 496 p. — 3000 copies. — ISBN 978-5-7695-3496-6.
4. ↑ Sensenig, Andrew T; Jeffrey W Shultz. Mechanics of Cuticular Elastic Energy Storage in Leg Joints Lacking Extensor Muscles in Arachnids (English) // The Journal of Experimental Biology : journal. - The Company of Biologists (English) Russian, 2003. - February 15 (vol. 206, no. 4). — P. 771-784. — ISSN 1477-9145. - doi:10.1242/jeb.00182.
5. ↑ Shultz, Jeffrey W. Evolution of locomotion in arachnida: The hydraulic pressure pump of the giant whipscorpion, Mastigoproctus Giganteus (Uropygi) (English) // Journal of Morphology: journal. - Wiley-VCH, 2005. - 6 February (vol. 210, no. 1). - P. 13-31. — ISSN 1097-4687. - doi:10.1002/jmor.1052100103.
6. ↑ Shultz, Jeffrey W. Muscle Firing Patterns in Two Arachnids Using Different Methods of Propulsive Leg Extension (English) // The Journal of Experimental Biology: journal. - The Company of Biologists (English) Russian, 1992. - January 1 (vol. 162, no. 1). — P. 313-329. — ISSN 1477-9145.
7. ↑ 1 2 Digestive and circulatory systems of arachnids. www.zoofirma.ru. Access date: January 28, 2022.
8. ↑ Arachnids / A. V. Ivanov // Great Soviet Encyclopedia: [in 30 volumes] / ch. ed. A. M. Prokhorov. — 3rd ed. - M.: Soviet Encyclopedia, 1969-1978.
9. ↑ 1 2 Mikhailov K. G. Arachnology in Russia/USSR // In the book: Aspects of Biodiversity. Part 2 / Compiled by: I. Ya. Pavlinov. . — Collection of works of the Zoological Museum of Moscow State University. - Moscow: Partnership of Scientific Publications KMK, Zoological Museum of Moscow State University, 2016. - T. 54 (2). — P. 655-691. — 434 (p. 401-830) p. — ISBN 978-5-9908416-6-6. (issn:1025-532Х)
10. ↑ Wheeler WC, Hayashi CY (1998). The phylogeny of the extant chelicerate orders, Cladistics, vol. 14, pp. 173-192. pdf. Access date: May 26, 2022. Archived November 28, 2012. (English)
11. ↑ Garwood, RJ; Dunlop, JA 2011: Morphology and systematics of Anthracomartidae (Arachnida: Trigonotarbida). - Palaeontology, 54(1): 145-161. doi: 10.1111/j.1475-4983.2010.01000.x
12. ↑ Jason A. Dunlop. A redescription of the Carboniferous arachnid Plesiosiro madeleyi Pocock, 1911 (Arachnida: Haptopoda) // Transactions of the Royal Society of Edinburgh: Earth Sciences: journal. - 1999. - Vol. 90. - P. 29-47.
13. ↑ Harvey MS (2002). The neglected cousins: what do we know the smaller arachnid orders? Journal of Arachnology, vol. 30, pp. 357-372. pdf (inaccessible link). Access date: September 19, 2009. Archived November 28, 2012. (English)

Social structure and reproduction

Photo: Encephalitis tick

Ticks reproduce in different ways, depending on the type of animal. Most ticks are oviparous. Viviparous individuals are less common. Individuals are clearly divided into females and males.

The following stages of animal development are distinguished:

• eggs. During the warm period, the female, after full saturation with blood, lays eggs. The average clutch consists of 3 thousand eggs. The shape of eggs can be different, both oval and round. The size of the egg as a percentage of the female’s body is not small;
• larva. The larva hatches from the egg after a couple of weeks. She immediately looks like an adult tick, the only difference being the size as she is smaller. The larvae lead an active lifestyle in warm weather. They choose small animals as their victims. Complete saturation with blood occurs within 3-6 days, and then the larva disappears;
• nymph. The tick becomes this after its first full meal. It is larger than a larva and has 8 limbs. The speed of her movement increases significantly, so she can choose large animals as victims. Often as nymphs, most ticks survive cold times;
• adult. After a year, the nymph grows into an adult, female or male.

Interesting fact: The fertility of a female tick is 17 thousand eggs.

Arachnids are part of nature

Each link of the ecological system has its own function. Millions of ticks inhabit the earth, water, plants and living organisms. They are an integral part of natural balance. Like other representatives of the fauna, arachnids are part of the food chain. What importance do ticks play in nature and human life? Soil species process organic matter in the soil. Through the efforts of small arthropods, fertile humus appears. As food for reptiles, birds and insects, mites contribute to the survival of these species.

Arachnids eat fungal spores, algae and bacterial plaque. Predators reduce the number of insects, nematodes, and worms. This feature makes them plant orderlies. Infecting animals with various diseases is a kind of natural way to control their numbers.

Families that live on agricultural crops, grain and flour reserves, and dairy products are harmful to humans. Ectoparasites of domestic animals and birds are also considered harmful species. Of the total number of existing groups of ticks, only a small part poses a direct threat to human life and health. These are ixodid and argasid species. It is necessary to dwell in more detail on where these ticks live, how they reproduce and feed.

Blood-sucking species

The ixodid or encephalitis tick is the most dangerous species for humans. These parasites are found everywhere, even in Antarctica, where they live on penguins. Ixodids are quite large individuals - female 3-4 mm, male 2-2.5 mm. On the back of the imago there is a dense scute; in the male it covers the entire back, and in the female only one third. The color of the head, legs and body is dark, from brown to black. When saturated with blood, the female increases significantly in size (up to 100 times) and changes color to gray.

Ticks reproduce in a unique way. Males fertilize females who feed on the animals' bodies. Bloodsuckers hold the record for the number of eggs they lay. One female leaves up to 17 thousand eggs in the ground. It is good that only a small part of the offspring survives. After birth, the larva feeds once, choosing a rodent as its host. After molting, she becomes a nymph. To transform into an imago (adult) one more feeding is necessary. In total, ixodid ticks suck blood three times in their life. Most species change hosts, the last being a large animal or human.

Attention. In Russia, two types of blood-sucking ticks are considered the most dangerous - the taiga tick and the dog tick.

Argas species - the body of the adult is 3-30 mm in size, it is flat and oval in shape. A hungry individual is gray in color, but after feeding it turns purple. Argas parasites live on birds, cats, and bite humans. Their saliva is extremely toxic. Mexicans compare Ornithodorus coriaceus bites to a rattlesnake attack.

What diseases do ticks carry?

After a parasite bite, you can become infected with several dangerous viral and infectious diseases:

• tick-borne encephalitis virus;
• tularemia;
• Lyme disease or borreliosis;
• relapsing fever;
• Marseilles fever;
• monocytic ehrlichiosis.

Attention. The risk of contracting one of the diseases carried by parasites increases with the amount of saliva carried into the bite site. It is necessary to conduct a thorough examination of the body after visiting forests and meadows. If the bloodsucker is removed in the first hours, the likelihood of the virus entering the blood is minimal.

How a tick bites

A special feature of the bite is the simultaneous administration of active painkillers, so the victim does not feel it. Ixodids do not bite immediately; they can search for a convenient place for up to two hours. On the human body the parasite prefers:

• area behind the ears;
• neck;
• groin and armpits;
• scalp;
• small of the back.

A special suboral outgrowth of the hypostome, which has sharp hooks directed backwards, helps to firmly anchor itself in the chosen place. This structure makes it difficult to remove the parasite. With the help of sharp chelicerae, the bloodsucker immerses the head into the skin. Its saliva acts as an analgesic and anticoagulant. You can remove a tick from a person using tweezers, a loop of thread, or a device purchased at a pharmacy. The main rule is to remove it completely, avoiding leaving the head under the skin. The bite site must be disinfected with alcohol or chlorhexidine.

Attention. The number of people infected with encephalitis is 2-6% of those bitten by the ixodid species.

Where do ticks live?

The habitat of nymphs, larvae and adults is the forest floor, grass or low shrubs. They climb to the tops of plants, waiting for a new host. The parasite smells a person at a distance of up to 10 m.

Natural enemies of ticks

Photo: What a tick looks like

Ticks occupy one of the lowest positions in the food chain. What is horror and a nightmare for humans is a holiday for birds and others who feed on them. There are many man-made means to combat ticks. But nature itself has succeeded in this. There are a considerable number of insects and animals that feed on them or lay eggs in them. Spiders, frogs, lizards, wasps, dragonflies, this is not a complete list of those who see the tick not as a danger, but as food.

Fungi also kill ticks, causing various types of fungal infections and diseases. Based on this information, you need to understand that mass persecution of ticks or burning of grass is a disaster, because the natural balance will be disrupted, and this will lead to the death of both the ticks themselves and the species that feed on them.

And here, after sweeping away the natural enemy from hunger, a new mite may appear and develop even stronger in the remaining areas of the surviving grass. Also, when burning the grass, they also burn the grave spores, which infect the tick and prevent them from reproducing and infecting them with fatal infections. And plus, after burning, new grass grows, even softer and better than the previous one, which certainly has a beneficial effect on the increase in the tick population.

Why do spiders have webs?

The web that spiders weave is intended not only for building trapping networks, but also for:

• building cocoons for eggs. In this case, the web is used as a construction tool for the other side of life - its continuation. Actually, the construction of trapping nets by spiders is also a way to prolong life, because an individual dies when there is no food. But here we mean maintaining the integrity of the population. This function of the web has a much more global purpose;
• escape in case of danger. Here we are talking not so much about maintaining the integrity of the population as about preserving life. Thanks to the web, the spider can escape from something that poses a potential or obvious threat to it.