Surely each of us has noticed how plants of the same species develop well in the forest, but do not feel well in open spaces. Or, for example, some mammal species have large populations while others are more limited under seemingly identical conditions. All life on Earth is one way or another subject to its own laws and rules. Ecology studies them. One of the fundamental statements is Liebig's law of minimum

Limiting what is it?

The German chemist and founder of agricultural chemistry, Professor Justus von Liebig, made many discoveries. One of the most famous and recognized is the discovery of the fundamental limiting factor. It was formulated in 1840 and later expanded and generalized by Shelford. The law states that for any living organism, the most significant factor is the one that deviates the most from its optimal value. In other words, the existence of an animal or plant depends on the degree of severity (minimum or maximum) of a particular condition. Individuals encounter a wide variety of limiting factors throughout their lives.

"Liebig Barrel"

The factor limiting the life activity of organisms can be different. The formulated law is still actively used in agriculture. J. Liebig established that plant productivity depends primarily on the mineral substance (nutrient), which is most poorly expressed in the soil. For example, if nitrogen in the soil is only 10% of the required norm, and phosphorus is 20%, then the factor limiting normal development is the lack of the first element. Therefore, nitrogen-containing fertilizers should be initially applied to the soil. The meaning of the law was stated as clearly and clearly as possible in the so-called “Liebig barrel” (pictured above). Its essence is that when the vessel is filled, water begins to overflow where the shortest board is, and the length of the rest no longer matters much.

Water

This factor is the most stringent and significant compared to the others. Water is the basis of life, as it plays an important role in the life of an individual cell and the entire organism as a whole. Maintaining its quantity at the proper level is one of the main physiological functions of any plant or animal. Water as a factor limiting life activity is due to the uneven distribution of moisture over the Earth's surface throughout the year. In the process of evolution, many organisms have adapted to the economical use of moisture, surviving the dry period in a state of hibernation or dormancy. This factor is most strongly expressed in deserts and semi-deserts, where flora and fauna are very sparse and unique.

Light

Light arriving in the form of solar radiation powers all life processes on the planet. Organisms care about its wavelength, duration of exposure, and radiation intensity. Depending on these indicators, the body adapts to environmental conditions. As a factor limiting existence, it is especially pronounced at great sea depths. For example, plants are no longer found at a depth of 200 m. Together with lighting, at least two more limiting factors “work” here: pressure and oxygen concentration. This can be contrasted with the tropical rainforests of South America, as the most favorable territory for life.

Ambient temperature

It's no secret that all physiological processes occurring in the body depend on external and internal temperature. Moreover, most species are adapted to a rather narrow range (15-30 °C). The dependence is especially pronounced in organisms that are not able to independently maintain a constant body temperature, for example, reptiles. In the process of evolution, many adaptations have been formed that allow one to overcome this limited factor. So, in hot weather, in order to avoid overheating, it intensifies in plants through stomata, in animals - through the skin and respiratory system, as well as behavioral characteristics (hiding in the shade, burrows, etc.).

Pollutants

The significance cannot be underestimated. The last few centuries for humans have been marked by rapid technical progress and the rapid development of industry. This has led to harmful emissions into water bodies, soil and the atmosphere increasing several times. It is possible to understand which factor limits this or that species only after research. This state of affairs explains the fact that the species diversity of individual regions or areas has changed beyond recognition. Organisms change and adapt, some replace others.

All these are the main factors limiting life. In addition to them, there are many others, which are simply impossible to list. Each species and even individual is individual, therefore the limiting factors will be very diverse. For example, the percentage of oxygen dissolved in water is important for trout; for plants, the quantitative and qualitative composition of pollinating insects, etc.

All living organisms have certain limits of endurance due to one or another limiting factor. Some are quite wide, others are narrow. Depending on this indicator, eurybionts and stenobionts are distinguished. The former are able to tolerate a large amplitude of fluctuations of various limiting factors. For example, living everywhere from the steppes to the forest-tundra, wolves, etc. Stenobionts, on the contrary, are able to withstand very narrow fluctuations, and these include almost all rain forest plants.

In this work I will cover in detail the topic “Limiting factors”. I will consider their definition, types, laws and examples.

Different environmental factors have different significance for living organisms.

For organisms to live, a certain combination of conditions is necessary. If all environmental conditions are favorable, with the exception of one, then this condition becomes decisive for the life of the organism in question.

Of the variety of limiting environmental factors, the attention of researchers is primarily attracted to those that inhibit the vital activity of organisms and limit their growth and development.

Main part

In the total pressure of the environment, factors are identified that most strongly limit the success of the life of organisms. Such factors are called limiting or limiting.

Limiting factors - This

1) any factors inhibiting population growth in the ecosystem; 2) environmental factors, the value of which greatly deviates from the optimum.

In the presence of optimal combinations of many factors, one limiting factor can lead to oppression and death of organisms. For example, heat-loving plants die at negative air temperatures, despite the optimal content of nutrients in the soil, optimal humidity, light, and so on. Limiting factors are irreplaceable if they do not interact with other factors. For example, a lack of mineral nitrogen in the soil cannot be compensated for by an excess of potassium or phosphorus.

Limiting factors for terrestrial ecosystems:

Temperature;

Nutrients in the soil.

Limiting factors for aquatic ecosystems:

Temperature;

Sunlight;

Salinity.

Typically, these factors interact in such a way that one process is limited simultaneously by several factors, and a change in any of them leads to a new equilibrium. For example, an increase in food availability and a decrease in predation pressure can lead to an increase in population size.

Examples of limiting factors are: outcrops of uneroded rocks, erosion base, valley sides, etc.

Thus, the factor limiting the spread of deer is the depth of the snow cover; moths of the winter armyworm (a pest of vegetable and grain crops) - winter temperature, etc.

The idea of ​​limiting factors is based on two laws of ecology: the law of the minimum and the law of tolerance.

Law of the minimum

In the mid-19th century, the German organic chemist Liebig, studying the effect of various microelements on plant growth, was the first to establish the following: plant growth is limited by an element whose concentration and significance is at a minimum, that is, present in a minimal amount. The so-called “Liebig barrel” helps to represent the law of the minimum figuratively. This is a barrel with wooden slats of different heights, as shown in the figure. It is clear that no matter what the height of the other slats, you can pour exactly as much water into the barrel as the height of the shortest slats. Likewise, a limiting factor limits the life activity of organisms, despite the level (dose) of other factors. For example, if yeast is placed in cold water, the low temperature will become a limiting factor for its reproduction. Every housewife knows this, and therefore leaves the yeast to “swell” (and actually multiply) in warm water with a sufficient amount of sugar.

Heat, light, water, oxygen, and other factors can limit or limit the development of organisms, if their movement corresponds to the ecological minimum. For example, the tropical fish angelfish dies if the water temperature drops below 16 °C. And the development of algae in deep-sea ecosystems is limited by the depth of penetration of sunlight: there are no algae in the bottom layers.

Later (in 1909), the law of the minimum was interpreted by F. Blackman more broadly, as the action of any ecological factor that is at a minimum: environmental factors that have the worst significance in specific conditions especially limit the possibility of the existence of a species in these conditions in spite of and in spite of optimal combination of other hotel conditions.

In its modern formulation, the law of the minimum sounds like this: the body's endurance is determined by the weakest link in the chain of its environmental needs .

To successfully apply the law of limiting factors in practice, two principles must be observed:

The first is restrictive, that is, the law is strictly applicable only under stationary conditions, when the inflow and outflow of energy and substances are balanced. For example, in a certain body of water, the growth of algae is limited under natural conditions by a lack of phosphates. Nitrogen compounds are found in excess in water. If wastewater with a high content of mineral phosphorus begins to be discharged into this reservoir, the reservoir may “bloom.” This process will progress until one of the elements is used up to the restrictive minimum. Now it may be nitrogen if phosphorus continues to be supplied. At the transition moment (when there is still enough nitrogen and enough phosphorus), the minimum effect is not observed, i.e., none of these elements affects the growth of algae.

The second takes into account the interaction of factors and the adaptability of organisms. Sometimes the body is able to replace the deficient element with another, chemically similar one. Thus, in places where there is a lot of strontium, in mollusk shells it can replace calcium when there is a deficiency of the latter. Or, for example, the need for zinc in some plants is reduced if they grow in the shade. Therefore, a low zinc concentration will limit plant growth less in the shade than in bright light. In these cases, the limiting effect of even an insufficient amount of one or another element may not manifest itself.

Law of Tolerance

The concept that, along with a minimum, a maximum can also be a limiting factor was introduced 70 years later in 1913 after Liebig by the American zoologist W. Shelford. He drew attention to the fact that not only those environmental factors whose values ​​are minimal, but also those that are characterized by an ecological maximum can limit the development of living organisms, and formulated the law of tolerance: “ The limiting factor for the prosperity of a population (organism) can be either a minimum or a maximum of environmental impact, and the range between them determines the amount of endurance (tolerance limit) or the ecological valency of the organism to this factor)" (Fig. 2).

Figure 2 - Dependence of the result of an environmental factor on its intensity

The favorable range of action of an environmental factor is called optimum zone (normal life activities). The more significant the deviation of a factor’s action from the optimum, the more this factor inhibits the vital activity of the population. This range is called zone of oppression or pessimism . The maximum and minimum transferable values ​​of a factor are critical points beyond which the existence of an organism or population is no longer possible. The tolerance limit describes the amplitude of factor fluctuations, which ensures the most fulfilling existence of the population. Individuals may have slightly different tolerance ranges.

Later, tolerance limits for various environmental factors were established for many plants and animals. The laws of J. Liebig and W. Shelford helped to understand many phenomena and the distribution of organisms in nature. Organisms cannot be distributed everywhere because populations have a certain tolerance limit in relation to fluctuations in environmental environmental factors.

Many organisms are capable of changing tolerance to individual factors if conditions change gradually. You can, for example, get used to the high temperature of the water in the bath if you get into warm water and then gradually add hot water. This adaptation to a slow change in factor is a useful protective property. But it can also be dangerous. Unexpectedly, without warning signs, even a small change can be critical. A threshold effect occurs: the last straw could be fatal. For example, a thin twig can cause a camel's already overloaded back to break.

The principle of limiting factors is valid for all types of living organisms - plants, animals, microorganisms and applies to both abiotic and biotic factors. For example, competition from another species may become a limiting factor for the development of organisms of a given species. In agriculture, pests and weeds often become the limiting factor, and for some plants the limiting factor in development is the lack (or absence) of representatives of another species. In accordance with the law of tolerance, any excess of matter or energy turns out to be a pollutant. Thus, excess water, even in arid areas, is harmful, and water can be considered a common pollutant, although it is essential in optimal quantities. In particular, excess water prevents normal soil formation in the chernozem zone.

The following was found:

· organisms with a wide range of tolerance to all factors are widespread in nature and are often cosmopolitan, for example, many pathogenic bacteria;

· Organisms may have a wide range of tolerance for one factor and a narrow range for another. For example, people are more tolerant to the absence of food than to the lack of water, i.e., the tolerance limit for water is narrower than for food;

· if conditions for one of the environmental factors become suboptimal, then the tolerance limit for other factors may also change. For example, when there is a lack of nitrogen in the soil, cereals require much more water;

· the limits of tolerance in breeding individuals and offspring are less than in adult individuals, i.e. females during the breeding season and their offspring are less hardy than adult organisms. Thus, the geographic distribution of game birds is more often determined by the influence of climate on eggs and chicks, rather than on adult birds. Caring for offspring and careful attitude towards motherhood are dictated by the laws of nature. Unfortunately, sometimes social “achievements” contradict these laws;

· extreme (stressful) values ​​of one of the factors lead to a decrease in the tolerance limit for other factors. If heated water is released into a river, fish and other organisms spend almost all their energy coping with stress. They lack energy to obtain food, protect themselves from predators, and reproduce, which leads to gradual extinction. Psychological stress can also cause many somatic (gr. soma- body) diseases not only in humans, but also in some animals (for example, dogs). With stressful values ​​of the factor, adaptation to it becomes more and more “expensive”.

It is possible to identify probable weak links in the environment that may turn out to be critical or limiting. With targeted influence on limiting conditions, it is possible to quickly and effectively increase plant yields and animal productivity. Thus, when growing wheat on acidic soils, no agronomic measures will be effective unless liming is used, which will reduce the limiting effect of acids. Or, if you grow corn in soils that are very low in phosphorus, even with enough water, nitrogen, potassium and other nutrients, it will stop growing. Phosphorus in this case is the limiting factor. And only phosphorus fertilizers can save the harvest. Plants can also die from too much water or excess fertilizer, which in this case are also limiting factors.

If a change in the value of the limiting factor leads to a much larger (in compared units) change in the output characteristics of the system or other elements, then the limiting factor is called control element in relation to these latter controlled characteristics, or elements.

Often a good way to identify limiting factors is to study the distribution and behavior of organisms on the periphery of their range. If we agree with the statement of Andrevarta and Birch (1954) that distribution and abundance are controlled by the same factors, then studying the periphery of the range should be doubly useful. However, many ecologists believe that the abundance in the center of the range and the distribution on its periphery can be controlled by completely different factors, especially since, as geneticists have discovered, individuals in peripheral populations may differ from individuals in central populations at the genotype level.

Conclusion

In this work, I examined in detail the definition, types, laws and examples of limiting factors.

After analyzing the work, I drew conclusions.

Identification of limiting factors is an approximation technique that reveals the roughest, most significant features of the system.

Identification of limiting links allows one to significantly simplify the description, and in some cases, to qualitatively judge the dynamic states of the system.

Knowledge of limiting factors provides the key to ecosystem management, so only skillful regulation of living conditions can give effective management results.

The concept of limiting factors, originating from the classical works of Liebig, is actively used in biochemistry, physiology, agronomy, as well as in quantitative genetics.

A key role in evolution is played by limiting factors of organization that limit the possibilities of certain directions of evolution.

The value of the concept of limiting factors is that it provides a starting point for exploring complex situations.

Identifying limiting factors is the key to controlling the life activity of organisms.

Identification of limiting factors is very important for many activities, especially agriculture.

Bibliography

1.Ecology. Textbook for universities

2.Ecology. Textbook for universities. Author: Korobkin V.I., Peredelsky L.V. Publisher: Phoenix, 2010
3. Markov M.V. Agrophytocenology. Ed. Kazan University, 1972.
4. Nebel B. Environmental Science. M.: Mir, 1993.
5. Ricklefs R. Fundamentals of General Ecology. M.: Mir. 1979.
6. Soviet encyclopedic dictionary. M.: Soviet Encyclopedia, 1988.
7. Encyclopedic dictionary of environmental terms. Kazan, 2001.

Lecture 5. Limiting factors

Different environmental factors have different significance for living organisms.

For organisms to live, a certain combination of conditions is necessary. If all environmental conditions are favorable, with the exception of one, then this condition becomes decisive for the life of the organism in question.

Limiting factors - This

1) any factors inhibiting population growth in the ecosystem; 2) environmental factors, the value of which greatly deviates from the optimum.

In the presence of optimal combinations of many factors, one limiting factor can lead to oppression and death of organisms. For example, heat-loving plants die at negative air temperatures, despite the optimal content of nutrients in the soil, optimal humidity, light, and so on. Limiting factors are irreplaceable if they do not interact with other factors. For example, a lack of mineral nitrogen in the soil cannot be compensated for by an excess of potassium or phosphorus.

Limiting factors for terrestrial ecosystems:

Temperature;

Nutrients in the soil.

Limiting factors for aquatic ecosystems:

Temperature;

Sunlight;

Salinity.

Typically, these factors interact in such a way that one process is limited simultaneously by several factors, and a change in any of them leads to a new equilibrium. For example, an increase in food availability and a decrease in predation pressure can lead to an increase in population size.

Examples of limiting factors are: outcrops of uneroded rocks, erosion base, valley sides, etc.

Thus, the factor limiting the spread of deer is the depth of the snow cover; moths of the winter armyworm (a pest of vegetable and grain crops) - winter temperature, etc.

The idea of ​​limiting factors is based on two laws of ecology: the law of the minimum and the law of tolerance.
In the mid-19th century, the German organic chemist Liebig, studying the effect of various microelements on plant growth, was the first to establish the following: plant growth is limited by an element whose concentration and significance is at a minimum, that is, present in a minimal amount. The so-called “Liebig barrel” helps to represent the law of the minimum figuratively.

This is a barrel with wooden slats of different heights, as shown in the picture. It is clear that no matter what the height of the other slats, you can pour exactly as much water into the barrel as the height of the shortest slats. Likewise, a limiting factor limits the life activity of organisms, despite the level (dose) of other factors. For example, if yeast
placed in cold water, low temperature will become a limiting factor for their reproduction. Every housewife knows this, and therefore leaves the yeast to “swell” (and in fact multiply) in warm water with a sufficient amount of sugar. All that remains is to “replace” some terms: let the height of the poured water be some biological or ecological function (for example, productivity), and the height of the slats will indicate the degree of deviation of the dose of a particular factor from the optimum.

Currently, Liebig's law of the minimum is interpreted more broadly. A limiting factor can be a factor that is not only in short supply, but also in excess.

An environmental factor plays the role of a LIMITING FACTOR if this factor is below a critical level or exceeds the maximum tolerable level.

The limiting factor determines the distribution area of ​​the species or (under less severe conditions) affects the general level of metabolism. For example, the phosphate content in seawater is a limiting factor that determines the development of plankton and the productivity of communities in general.

The concept of "limiting factor" applies not only to various elements, but also to all environmental factors. Often, competitive relations act as a limiting factor.

Each organism has limits of endurance in relation to various environmental factors. Depending on how wide or narrow these limits are, eurybiont and stenobiont organisms are distinguished. Eurybionts capable of withstanding a wide range of intensity of various environmental factors. Let's say the fox's habitat ranges from forest-tundra to steppes. Stenobionts, on the contrary, tolerate only very narrow fluctuations in the intensity of the environmental factor. For example, almost all plants of tropical rainforests are stenobionts.

Law of Tolerance

The concept that, along with a minimum, a maximum can also be a limiting factor was introduced 70 years later in 1913 after Liebig by the American zoologist W. Shelford. He drew attention to the fact that not only those environmental factors whose values ​​are minimal, but also those that are characterized by an ecological maximum can limit the development of living organisms, and formulated the law of tolerance: “ The limiting factor for the prosperity of a population (organism) can be either a minimum or a maximum of environmental impact, and the range between them determines the amount of endurance (tolerance limit) or the ecological valency of the organism to this factor)"

The favorable range of action of an environmental factor is called the zone of optimum (normal life activity). The more significant the deviation of a factor’s action from the optimum, the more this factor inhibits the vital activity of the population. This range is called the zone of depression or pessimum. The maximum and minimum transferable values ​​of a factor are critical points beyond which the existence of an organism or population is no longer possible. The tolerance limit describes the amplitude of factor fluctuations, which ensures the most fulfilling existence of the population. Individuals may have slightly different tolerance ranges.

Environmental factors.

The concept of the natural environment includes all conditions of living and inanimate nature in which an organism, population, or natural community exists. The natural environment directly or indirectly affects their condition and properties. Components of the natural environment that influence the state and properties of an organism, population, or natural community are called environmental factors. Among them, three different groups of factors are distinguished:

abiotic factors - all components of inanimate nature, among which the most important are light, temperature, humidity and other climate components, as well as the composition of the water, air and soil environment;

biotic factors - interactions between different individuals in populations, between populations in natural communities;

limiting factors - environmental factors that go beyond the boundaries of maximum or minimum endurance, limiting the existence of a species.

anthropogenic factor - all the diverse human activities that lead to changes in nature as the habitat of all living organisms or directly affect their lives.

Various environmental factors, such as temperature, humidity, food, affect each individual. In response to this, organisms develop various adaptations to them through natural selection. The intensity of factors that is most favorable for life activity is called optimal or optimum.

The optimal value of a particular factor is different for each species. Depending on their attitude to one or another factor, species can be heat- and cold-loving (elephant and polar bear), moisture- and dry-loving (linden and saxaul), adapted to high or low salinity of water, etc.

Limiting factor

The body is simultaneously influenced by numerous diverse and multidirectional environmental factors. In nature, the combination of all influences in their optimal, most favorable values ​​is practically impossible. Therefore, even in habitats where all (or leading) environmental factors are most favorably combined, each of them most often deviates somewhat from the optimum. To characterize the effect of environmental factors on animals and plants, it is essential that in relation to some factors, organisms have a wide range of endurance and can withstand significant deviations in the intensity of the factor from the optimal value.

Effective temperature refers to the difference between the ambient temperature and the temperature threshold for development. Thus, the development of trout eggs begins at 0°C, which means that this temperature serves as a development threshold. At a water temperature of 2 C, the fry emerge from the facial shells after 205 days, at 5 ° C - after 82 days, and at 10 ° C - after 41 days. In all cases, the product of positive environmental temperatures and the number of days of development remains constant: 410. This will be the sum of effective temperatures.

Thus, in order to carry out the genetic development program, animals with unstable body temperatures (and plants) need to receive a certain amount of heat.

Both the development thresholds and the sum of effective temperatures are different for each species. They are determined by the historical adaptation of the species to certain living conditions.

The flowering time of plants also depends on the sum of temperatures over a certain period of time. For example, coltsfoot requires 77 to flower, oxalis requires 453, and strawberries require 500. The sum of effective temperatures that must be reached to complete the life cycle often limits the geographic distribution of a species. Thus, the northern border of tree vegetation coincides with the July isotherms of Yu...12°C. To the north there is no longer enough heat for the development of trees and the forest zone is replaced by tundra. Likewise, if barley grows well in the temperate zone (its sum of temperatures for the entire period from sowing to harvesting is 160-1900°C), then this amount of heat is not enough for rice or cotton (with the sum of temperatures required for them being 2000-4000°C ).

Many factors become limiting during the breeding season. Hardiness limits for seeds, eggs, embryos, and larvae are usually narrower than for adult plants and animals. For example, many crabs can enter a river far upstream, but their larvae cannot develop in river water. The range of game birds is often determined by the effects of climate on eggs or chicks rather than on adults.

Identifying limiting factors is very important in practical terms. Thus, wheat does not grow well in acidic soils, but adding lime to the soil can significantly increase yields. .

Limiting factors can include any environmental factors: lighting, temperature, humidity, microenvironment, soil composition, etc. The doctrine of limiting factors is based on two fundamental postulates: Liebig's law (1840) and Shelford's law (1913).

Each species of plants, microorganisms and animals exists in conditions under which their life is most comfortable. In order for representatives of each population to be able to fully feed, develop and reproduce, it is necessary for each environmental factor to correspond to certain values ​​that fall within a more or less wide range. This applies to insects to the same extent as to other living organisms, so in the future we will consider the influence of limiting factors using the example of this class.

For the viability of organisms, both a decrease and an excess of optimal values ​​of temperature, humidity, etc. are dangerous. Exceeding their endurance limits leads to the death of an organism, a population or even an ecosystem.

For example, if the soil lacks a certain microelement, this causes a decrease in plant productivity. Due to the lack of food, the insects that fed on these plants die. The latter, in turn, affects the survival of entomophagous predators: other insects, birds, some amphibians, etc.

Each organism is characterized by a certain ecological minimum and maximum, between which there is a zone of normal life activity (or optimum). The further a factor deviates from the optimum value, the more noticeable its negative impact. Beyond critical points (extreme values ​​of the limiting factor), the existence of an organism is impossible.

To indicate the degree of tolerance (stability) of species to various values ​​of limiting factors, they are usually divided into low-tolerant - stenobionts- and hardy, or eurybionts. Stenobionts include lower insects that live in caves (Bessyazhkovye, etc.), as well as most tropical orders that exist only in conditions of high temperature and humidity. For example, Lepidoptera of the order Morpho (photo) They live only in the dense tropical forests of Central and South America and are very poorly bred in artificial conditions. In particular, they are very picky about the light regime: each species of these butterflies flies only at a certain time of the day.

Limiting factors of inanimate nature

Among all abiotic factors, insects have the greatest sensitivity to temperature, light and humidity.

As for the first, on the territory of our country, most species are able to live in the temperature range from 3 to 40 degrees, although some have adaptation mechanisms that allow them to exist outside the zone of normal life activity. Thus, a number of highly developed insects show resistance to freezing, since the liquid in their body does not turn into crystals, but vitrifies - it becomes like glass. It is common among some beetles, Lepidoptera and Diptera. For example, swallowtail butterflies (photo) can tolerate deep freezing down to almost -200 degrees.

Lighting is also important. Under the influence of optimal doses of ultraviolet radiation, important biochemical processes occur in the body of insects: the release of hormones, the formation of pigment, and even the absorption of certain minerals. Adherence to a certain light regime determines their lifestyle (day, night), as well as their preferred habitat. Thus, click beetles living in the soil cannot tolerate bright light and die under the influence of intense ultraviolet radiation.

Such a limiting factor as humidity affects insects very differently. Some of them, for example, mosquitoes, midges or primitive orders like mayflies, live mainly near bodies of water, which are associated not only with the most comfortable conditions for their life, but also with the process of life. For this reason, draining swamps is one of the most effective methods of controlling the spread of mosquitoes. Among insects there are also xerophytes that prefer arid areas, for example, ants inhabiting semi-deserts.

Limiting factors of wildlife

The life activity of insects can be limited not only by inanimate natural phenomena, but also by factors of biological origin. Biological limiting factors in the form of predators threaten all herbivorous species: for example, for butterflies, even within a class, dozens of predators can pose a threat, from mantises and ants to lacewings and some grasshoppers.

Under normal conditions, each species and population strives to occupy its own ecological niche, but sometimes conditions arise that two or more species compete with each other. In this case, they become limiting factors for each other. Most often, competition develops due to a lack of food resources; It often occurs between flying insects that pollinate the same plants.

In social forms - ants and termites - competition is noticeable not only outside the species, but also within it. These insects live in autonomous colonies, and each family poses a potential threat to every other by destroying available food and occupying its potential home.