Pasture tick. Development cycle of the pasture mite

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:46

One should never forget that a person is a potential victim of ticks, which are carriers of most dangerous viruses, among which tick-borne encephalitis occupies the first place. Blood-sucking mites live almost everywhere. They can lie in wait for their prey in the forest, in the field, on pastures, as well as in rooms where animals are kept. Despite the diversity of species, it is the pasture tick that poses the greatest threat to humans, which sticks to the body imperceptibly and painlessly. As a result, the person may not even be aware of the bite.

Fundamentals of pasture tick ethology

The active type of attack of pasture ticks allows them to quickly detect potential food and stay out of shelters as little as possible. Based on the sun, they visually determine the shortest path to food and launch an attack.

At the same time, pasture ticks (dermacentor marginatus), living in damp and cool conditions, rarely attack openly. Most often they are satisfieda kind of ambush on plants in anticipation of a victim, to detect which they use chemical signals emanating from any living creature. However, it should be noted that the grassland mite cannot recognize whether the odor source is suitable for feeding, and even reacts to non-specific odors. Foraging in such conditions is associated with active movements to places where ticks smell from people and animals.

Sex differences in pasture ticks

The pasture tick, whose size rarely exceeds 6 mm when hungry, can grow up to 2 cm. At the same time, it can be distinguished from other varieties not only by its unique dimensions, but also by its appearance.

The upper part of their body is covered with a dense dorsal shield, which can be used to determine the sex of an individual. In males, it covers the entire upper body, while in females and larvae at all stages of development, it covers only the anterior part. In addition, females suck out several times more blood than their own body weight, as a result of which they swell up so much that they begin to resemble a large bean, while the male requires much smaller volumes of blood for normal functioning. It is noteworthy that females are much more likely to be carriers of serious diseases, contributing to the emergence and maintenance of natural foci of viral infections.

Reproduction

Given the large number of varieties, a person, going out into nature, must definitely consider security measures andthe severity of the consequences that a tick on the body can lead to. The photo below gives an indication of the volume of blood that the female needs to consume to increase from a few millimeters to similar sizes.

After the female is completely satiated, she falls to the ground and, having picked up a suitable shelter for herself, begins to lay eggs. In this case, the fertilization of females occurs even during the period of saturation on the body of the host. Usually laying is done in minks, sand, fallen leaves or in rooms where farm animals are kept. This place is ideal not only for its temperature characteristics, but also allows newly minted ticks to get quick access to food, since the larvae are extremely hungry.

Development of larvae

It is noteworthy that the newly minted larva at birth does not have genitals, and only after a few days of continuous feeding, after the individual has molted, it transforms into a nymph, which is very similar in size to an adult tick.

The pasture tick, the life cycle of which is distinguished by characteristic features and is quite complex, includes several stages of transformation: from larva to adult. It needs a minimum amount of time to fully develop. The rate of its development directly depends on climatic conditions and the timely finding by the larva of a constant source of food for this period. The larva feeds for about three days, after which it has the first molt, after which it transforms into a nymph.

The pasture tick remains in the nymph stage for about a week, after which another molt occurs, as a result of which the individual transforms into an adult, and the development cycle of the pasture tick ends.

The most common species

Despite the fact that ticks are found almost everywhere and have a large number of different species, the most widespread are:

Ixodes persulcatus is a fairly aggressive species towards humans. Ticks of this group become most active in the 2-3rd year of life. Lives almost everywhere and poses a serious threat

Ixodes ricinus is a tick not exceeding 3 mm in size. In the initial stage of development, they are firmly attached to small rodents and birds, and as they grow older, they move to large and medium-sized cattle. In the event that the larvae are born in natural conditions, they use hares and hedgehogs as the main food sources, fixing on which ticks will feed at all stages of development. This species is most widespread in America, Western Europe and Russia.
Dermacentor marginatus. It is quite simple to distinguish ticks of this species from other representatives; it is necessary to carefully examine the dorsal shield of the individual. Its dark brown side is decorated with light patterns. The imago stage in dermacentor marginatus is already comingat the end of March, allowing them to actively parasitize even before the final warming and the awakening of most tick species. Most often they can be found in meadows and bushes, as a result of which they use human blood as their main food source much more often than other species, attacking people both during outdoor recreation and in urban areas.
Dermacentor pictus. Ticks of this species are able to absorb large volumes of blood, which in the future will lead not only to a breakdown, but also to anemia.

At the same time, these species can be divided into three categories:

A tick that lives on one host at any stage of development.
A tick that, while on the original host, picks up a new food source along the way.
A tick that randomly chooses its hosts throughout its life.

The impact of pasture ticks on humans

If the integrity of the skin of the tick is violated during removal from the body, a variety of pathogens of viral diseases can enter the human body.
If the bite site is not treated in a timely manner, the saliva produced by the grassland mite can lead to a serious allergic reaction, which can later cause fever and many nervous diseases.
Can carry many different viruses that are inherited from pasture ticks: from female to larvae.

Precautions

As the main preventive measures, it is recommended to wear clothes that completely cover exposed areas of the body when outdoors. In addition, after staying in the forest or in the field, be sure to carry out preventive examinations, as a result of which the detected tick on the body (a photo of a similar case is presented below) is carefully removed along with the proboscis. Try not to damage its integrity. In the event that it is broken during the extraction process, a viral infection can enter the body. It must be remembered that if a pasture mite infects farm animals, then with their milk, which has not undergone special treatment, the infection can be transmitted to humans.

At the same time, be sure to keep in mind that even if you are sure that the pasture tick was removed without violating its integrity, be sure to undergo a preventive medical examination that will help to detect and begin treatment of a possible viral infection in a timely manner.