: April 15, 2022, Take his shoes, walk his path..., volume 90, no. 5/6
What are the first associations that arise with the word “mite”? Parasite, bloodsucker, bite, infection... It is not surprising that ticks evoke extremely negative emotions in most of us. The well-known parasitic ticks, including ixodid ticks, which carry infectious pathogens dangerous to humans and domestic animals, have truly earned their grim reputation. However, few people know that these unsympathetic arthropods are only a small part of more than fifty thousand species, most of which perform functions that are essential for natural ecosystems, and some of which bring direct benefits to humans. So who are they, our enemies and neighbors? Why are they needed in nature and in the garden, and what benefit can we derive even from blood-sucking parasitic ticks?
Ticks
- the largest group of the arachnid class - can be distinguished from insects by the number of legs: adult individuals have four pairs of legs, not three. But it is not always possible to see these legs, as well as their carriers, with the naked eye: the body sizes of most of these creatures range from hundreds of microns to a millimeter.
Scientists know more than 54 thousand species of ticks, which differ in size and color, lifestyle and habitat. Ticks live everywhere: in arctic ice and deserts, nests, burrows and living quarters, under the skin and in the respiratory system of higher animals. Most of them are saprophages
, feeding on dead organic matter (from plant debris in the soil to secretions from the ears of mammals), and
predators
that hunt their fellow members of the order or small insects. But there are also blood-sucking parasites and plant parasites that feed on their sap - it is these mites that attract especially close human attention.
Description and types
Ticks have inhabited the planet since ancient times. They are not insects, as most people believe, but belong to the class of arachnids, which includes more than 25 thousand species. Their sizes vary from 0.1 to 0.5 mm; it is extremely rare to find representatives of arthropods about 3 mm in size. Ticks do not have wings. They move in space using the sensory apparatus, since they do not have an organ of vision. They can smell the scent of a future victim at a distance of 10 meters.
Depending on the structure of the body, oxygen supply occurs in different ways. Those arachnids that have a fused head and chest breathe through the skin or trachea, and armored representatives have special spiracles.
The main types of ticks include:
- ixodidae;
- argasaceae;
- armored;
- gamas;
- subcutaneous;
- scabies;
- ear;
- dusty;
- arachnoid;
- nautical;
- predatory;
- pasture;
- brown dog
Which acaricidal aerosols are more effective?
How to treat clothes against ticks? The study was carried out by employees of the Gorno-Altai Rospotrebnadzor. 8 cans of acaricidal aerosols were purchased - Reftamid, Gardex, DETA, Taiga, Moskitol, Tornado, Komaroff and Tarol. All products work approximately the same way - they do not repel ticks, but kill them. Eight signed sheets of paper were each treated with one product, dried and ticks were placed on them.
Three products completed their task before 10 minutes elapsed. The first group of drugs showed good effectiveness. These are Gardex, DEET and Taiga.
The next group of drugs, Reftamide, Moskitol and Komaroff, had slightly worse properties. The death of arthropods occurred at 18 minutes.
Aerosols Tornado and Tarol took last place and were not effective enough. By the time they begin to act, the mites will already have time to attach themselves to the skin. Moreover, Tarol turned out to be the worst remedy in the tests.
What do they eat?
Where ticks live and what they feed on is of interest to many people who want to prevent encounters with these arthropods. According to the type of nutrition, arachnids can be divided into:
- Saprophages that feed exclusively on organic debris.
- On predators that parasitize plants and animals.
Feeding on plant juices, mites cause significant damage to agriculture. Scabies and field arachnids eat particles of human epidermis. Granary feeders feed on decaying plant remains, flour, and grain. For subcutaneous mites, the food is the fat of human hair follicles, while ear mites consume fat from the hearing aids of animals.
Having taken their place on a branch or blade of grass, blood-sucking predators await their prey. Having waited, they attach themselves to it using paws with claws and suction cups, and then gradually reach the feeding site. The victim of arachnids is usually not only humans, but also other representatives of ticks.
Parasites are carriers of infectious diseases, so their bite can be fatal to humans. Arachnids can go without food for about three years, but once they receive food, they increase in weight several times.
Natural enemies
There are a large number of means of combating parasites. Nature also made sure that their numbers did not grow indefinitely. Arachnids are an important link in the food chain for many insects, birds and other animals.
Natural enemies that feed on ticks in nature and thereby control the arachnid population include:
- frogs;
- other types of arachnids;
- birds (sparrows, thrushes, starlings and others);
- ground beetles;
- dragonflies;
- ants;
- wasps;
- riders.
Natural enemies for ticks in nature are also fungal spores, which have a detrimental effect on them and cause fungal diseases in them. Therefore, it is so important to prevent large-scale burning of grass and treatment of large areas with acaricides. This will lead to disruption of the natural balance and as a result, not only the parasites themselves will die, but also their enemies. In addition, most of the tick eggs will survive, which will lead to their rapid reproduction and spread.
Rating of anti-tick acaricidal aerosols.
According to Rospotrebnadzor specialists, Gardex, DETA and Taiga turned out to be the best and equally effective. The worst, practically ineffective are Tornado and Tarol.
Rating among users.
I studied user reviews about anti-tick sprays for people. Users do not recommend mixed aerosols; they contain both a repellent and a killing active substance in half the concentration, which reduces both effects. It is also not recommended to use a combined product with simultaneous action against mosquitoes, midges and ticks, considering that they contain insufficient concentrations of the active anti-tick agent. It is not recommended to use repellent aerosols, since they quickly erode and their validity period is much shorter than that of acaricidal aerosols.
The vast majority use and believe that the best anti-tick spray is Reftamid-Antiklesch, but the 15-day validity period indicated on the can of the drug is considered unjustified and it is recommended to re-treat clothing before going out into the outbreak.
Good reviews of the aerosol Klesh-Kaput and Breeze-Antiklesch. On clothes treated with Breeze-Anti-Tick spray, the tick loses its ability to move and falls off after 1 minute. 5 hours after treatment, the tick disappears after 3 minutes, and a day later - after 4 minutes.
Meaning in nature and human life
It is difficult to find a place on Earth where these representatives of arachnids do not live. Ticks are found wherever possible: in the forest, in a personal plot, in a garden, and even in city parks and squares. All types differ in structure, color, and size.
Some of them cause irreparable harm to plants, others are parasitic on animals and humans, and still others are blood-sucking specimens.
People have been fighting them for a very long time, but the importance of ticks in nature should still be recognized.
For example, ixodid arthropods are the most dangerous to humans, as they carry deadly infectious diseases. Despite this, they play an important role in the ecosystem, as they regulate natural selection. If such a tick bites a weak animal, it will die, and strong ones will develop immunity. This helps maintain balance among animals on Earth. Thus, it follows that some representatives of arthropods, although of great importance for nature, still cause great harm to people.
Benefits of arachnids
Despite the fact that people are prejudiced against ticks, there are still benefits from them. In nature and in various industries, they can provide significant assistance:
- While causing enormous damage to agriculture, they still have a positive role. Being mostly saprophages in their diet, they improve the soil by feeding on the decaying remains of plants and animals.
- Predatory representatives of this class are used to exterminate other arachnids, which suck all the juice from plants, destroying most of the crop.
- They can also rid a plant affected by spores of parasitic fungi.
- Scientists have long been interested in the enzymes contained in the saliva of arthropods. Anticoagulants, as they are also called, prevent blood clotting.
- Some types of cheese are made by attaching a microscopic mite to the rind of the product at the beginning of its ripening. This allows cheese makers to obtain a unique pattern and specific aroma, makes it porous, which allows the cheese to breathe throughout the entire ripening process.
Representatives of the arachnid class are part of the food chain and an important link in the ecosystem. For example, the favorite delicacy of some birds and frogs is ixodid ticks.
Ticks vs ticks
A big problem in agriculture, primarily in greenhouses, is spider mites.
feeding on plant cell sap. When multiplying en masse, these parasites can completely destroy crop yields.
Among these mites there are species with certain food preferences, as can be seen from their names: hawthorn
and
date spider mites
.
And, for example, red spider
mites often infect indoor plants, including such exotic ones as calla lilies and orchids.
But still the most famous is the common spider mite
, characterized by amazing omnivorousness. This mite is capable of feeding on more than two hundred different types of plants from different families: from cotton and potatoes to raspberries and strawberries, from cucumbers and tomatoes to beans and dill, not counting many wild species. Greenhouse flower and ornamental crops, such as roses, chrysanthemums, etc., suffer greatly from spider mites.
It is this type of mite that is most often found in greenhouses. Mites reproduce and feed on the underside of the host plant leaf. Paired mite stylets, which can fold to form a hollow tube, penetrate deeply into plant tissue and destroy the integumentary and underlying cells. In just five minutes, a tick can pierce and suck out the contents of about a hundred cells.
IN THE SERVICE OF CHEESE MAKERS
In France and Germany, special types of cheese have long been produced with the help of certain types of cheese mites.
They appeared quite by accident, when manufacturers noticed that cheese that had been stored for a long time and affected by mites acquired an unusual piquant taste and smell that gourmets liked. Already in the 17th century. in France, by order of Louis XIV, “mite” cheese mimolette
.
They say that this was the favorite cheese of President Charles de Gaulle, who was born in Lille, in the vicinity of which mimolette is still produced today. It is made from cow's milk, the orange color is given with the help of a natural dye, and during ripening, Tyrophagus siro
, which “work” on it from several weeks to two years.
Mites gnaw passages in the cheese rind, and their waste products, including excrement and shed chitinous shells, give the product, according to amateurs, a nutty flavor and a fruity (lemon) aroma. Before sale, mites are removed from the surface of the milet, although some of them still remain. In 2013, the import of this cheese was banned in the United States as a “rotten product infested with mites.” But later cheese lovers won and the ban was lifted. For almost three hundred years, cheese with mites has also been produced in the village of Würchwitz (now the district of Zeitz) in eastern Germany. Würchwitz Milbenkese matures in wooden boxes infested with millions of Tyrolichus casei
, which are fed with rye flour. Ultimately, the cheese mass acquires a bitter aftertaste and the aroma of ammonia, valued by gourmets. The cheese is eaten together with the live mites it contains. The fact that the world’s only monument to the cheese mite was erected in the village shows how local residents feel about their unique product.
Such damage leads to disruption of the functions of the leaf stomata apparatus, where gas exchange occurs, inhibition of the process of photosynthesis and disruption of the outflow of sugars. Metabolic disorders cause suppression of plants and a significant decrease in their yield, and with a high number of parasites, even death.
To combat spider mites, plants are usually treated with various synthetic acaricides. However, repeated treatments lead to the rapid emergence of resistant pest races. Fortunately, an alternative to synthetic poisons has been found, and an unexpected one - predatory mites that hunt not only insects, but also their eight-legged “relatives”.
Among all the mites capable of destroying larvae and adults of spider mites, the most effective were representatives of the predatory family Phytoseiidae, which includes about a third of all gamasid mites.
In the entomocarifagous breeding laboratory of the Novosibirsk State Agrarian University, work is currently underway with the most promising plant protector - the mite Phytoseiulus persimiilis
.
The hunter mite searches for its victims - eggs, larvae and adult spider mites - by the presence of cobwebs on the surface of the leaves. Thanks to the variability of its morphological structures - long dorsal setae and pretarses
(the last segments of the leg with a pad and claw) - it easily slides between the tense threads of the web without getting entangled in them.
The mouthparts of Phytoseiulus are well adapted for eating food characteristic of it: having found a spider mite, it cuts through its cuticle with its claws-chelicerae and
plunges into the hole with its “head”, sucking out the contents.
At a temperature of 22–24 °C and a relative humidity of 45–55%, one generation of the common spider mite develops in 10–16 days, and at 28–32 °C – in just 8–10 days.
At the beginning, the damage looks like light dots - these are punctures, clearly visible on the upper side of the sheet. Then the leaves become marbled, turn yellow and die. The formation of a thin gray web on the leaves and other parts of the plant damaged by mites indicates a high number of the pest and its migration to neighboring plants Phytoseiulus persimiilis First discovered on herbaceous plants in Algeria and Chile
has spread as a biosecurity agent to greenhouse farms around the world. In closed ground conditions, this predatory mite allows you to effectively control the number of common spider mites. In the NSAU laboratory, where phytoseiulus is propagated year-round, a biotechnology for the protection of cucumbers, tomatoes and flowering plants such as asters and callas has been successfully created. If, for preventive purposes, this predator is periodically released in greenhouses, which successfully reproduces there, then there is no need to use chemicals to curb the growth of the number of spider mites.
Several more representatives of the Phytoseiidae family are being studied at NSAU, which also play an important role in the fight against agricultural pests. For example, the predatory mite Amblyseius cucumeris
used to destroy different types
of thrips
-
small insects that often parasitize vegetable and flower and ornamental crops in greenhouses, as well as spider mites,
cyclamen mites
and
rust mites.
When there is a lack of prey, this mite feeds on pollen without harming plants. And another predatory mite, native to the eastern Mediterranean, Amblyseius swirskii
, has become world famous as a biological weapon against such a dangerous quarantine pest as
the whitefly
. This mite helps protect various greenhouse and field vegetable crops, ornamental plants and citrus fruits.
Danger and harm
Ixodid representatives of the species pose a great danger to both representatives of the animal world and people. The taiga tick, or, as it is also called, the encephalitis tick, is in first place in terms of danger, as it is a carrier of diseases such as borrelosis, encephalitis, ehrlichiosis and other diseases.
Due to the fact that the food of these arachnids is blood, infection occurs after a bite. The causative agents of fatal diseases enter the human body along with the saliva of arthropods. Other types of arachnids can also harm human health, for example, subcutaneous scabies mites, which can be carriers of diseases such as dermatitis and scabies.
Saprophages, which seem harmless at first glance, can also harm people. Due to their small size, there are no places inaccessible to them, so they live almost everywhere:
- flour - feeds on flour, cereals, grains and thereby destroys a large amount of food;
- arachnoid - destroys a garden or indoor plant;
- dust - eats particles of the epidermis, dust, and can also cause an allergic reaction and asthma in humans.
- ear - causes inconvenience to cats and dogs, moving into their ears.
Ticks, as it turns out, can be both beneficial and harmful to humans and nature as a whole. They occupy a certain ecological niche and fulfill their direct responsibilities.
