Features and habitat of the dragonfly
The description of the dragonfly should begin with the eyes of this insect, which at first glance seem disproportionate and too large relative to the overall size of the body.
However, dragonflies have so-called facet vision, which is due to the presence of several tens of thousands of small eyes, each of which works independently and is separated from the others by special pigment cells.
The structure of the dragonfly's eyes allows it to see even what is happening behind
Thanks to this strange eye structure, the dragonfly's vision is much better than many other insects and allows it to see everything that is happening behind, on the sides and in front and track prey at a distance of up to ten meters.
Interesting! Dragonflies' vision is designed in such a way that it allows them to see the world in a completely different color, including ultraviolet.
The dragonfly's body consists directly of the head, chest and long belly, which ends in a pair of special forceps.
The length of the insect ranges from 3 to 14 centimeters. Coloration is quite varied and can vary from white, yellow and orange to red, blue and green.
The wings have many transverse and longitudinal veins, which serve as reinforcements.
The insect dragonfly is an animal that is one of the record holders for the speed of movement: although the average speed of its flight is usually from 5 to 10 km/h, some species are capable of reaching speeds of up to one hundred km/h when flying over long distances.
So, despite the image of an idly staggering jumping dragonfly , created in one famous fable, this insect is very mobile and leads an active lifestyle.
Dragonflies have three pairs of legs, which are covered with a layer of protective bristles. During flight, the limbs of the insect fold into a “basket” in order to quickly grab prey if it is detected. The wings have dark spots that serve as vibration protection.
It is worth noting that the first jet aircraft took off due to the fact that entomologists shared with designers and engineers this structural feature of the wings of dragonflies, who used this element in the structure of aircraft, which would still crumble as soon as they left the surface of the earth, if would not be dragonflies.
The habitat of dragonflies is very extensive and extends from the territory of modern Europe and Asia to the African continent, Australia and America.
Dragonflies live mainly among meadows, fields and on the edges of forests. A prerequisite must be the presence of a body of water nearby.
How butterflies winter
Insects survive unfavorable conditions in winter in different ways. The vast majority of them in temperate climates fall into a certain state called diapause in winter. Diapause is partly similar to the state of suspended animation in vertebrate warm-blooded and cold-blooded animals (bears, hedgehogs, frogs, lizards, shrews, moles). During diapause, insects slow down their metabolism and other vital processes. During diapause, the body's resistance to unfavorable external conditions increases, for example, insects become resistant to insecticides. This is what helps them withstand low winter temperatures.The “winter sleep” of insects is very deep, in contrast to the anabiosis of warm-blooded animals, which can be interrupted from time to time by a short awakening, it is the deepest and requires certain conditions for its termination. Winter hibernation of insects, as a rule, depends on the length of daylight hours and the presence of a certain temperature regime.
In winter, insects can be at any stage of their development - from egg to imago (adult insect). In each biological species, diapause is confined to a certain phase of development.
Many butterflies spend the winter in the egg stage. This small egg is placed in the most secluded places. The crimson silkworm spends the winter in the adult caterpillar stage, but this is considered an exception to the rule. Most caterpillars overwinter when they have just emerged from the egg, at an early age.
For butterflies, the most common wintering is in the pupal stage. Some pupae are so hardy that they spend the winter anchored on a tree branch in an open place, without fear of cold winds. Less hardy species, while still caterpillars, choose places inaccessible to winds and rains and there they turn into pupae and overwinter.
Species of butterflies such as lemongrass, urticaria, and burdock spend the winter in the adult stage. They cover their body with wings, like a blanket, hide in bark cracks or hollows and hibernate there.
Mourning butterflies avoid freezing by adding a special cooling liquid to their bodies - natural “antifreeze”, which they themselves produce. This liquid contains so-called cryoprotectors, which protect all fluids and soft tissues in her body from low temperatures.
In general, the behavior of insects in winter also depends on the ecology of the species. Even in very close species of the same genus, but living in different conditions, diapause occurs at different phases of development, and in species of unrelated families - at the same phase if they have a similar lifestyle.
Some butterflies, like migratory birds, head south with the onset of cold weather. The monarch butterfly, which lives in the United States, is capable of flying thousands of kilometers. Russia also has a migratory butterfly. This is a burdock, a nomadic butterfly. The first generation of this butterfly migrates south in the fall, and the second generation migrates north in the spring.
Ants survive the winter in a state of dormancy and inactivity. The forms of inactivity are varied; even the larvae of some species enter a state of diapause. However, adult ants in most species overwinter in a state of reduced activity.
In winter, ants stop their development: the larvae stop growing and stop pupating, the queen stops laying eggs, and the last pupae complete their metamorphosis. Working ants, preparing for winter, absorb aphid secretions especially actively. They contain sugar, which is converted into glycerol inside the ant's body. In the total weight, its share can reach 30%. This is how insects preserve themselves, since fatty glycerin prevents their bodies from turning into ice.
When cold weather sets in, the ants batten down the main exits from the anthill, leaving only ventilation holes, and descend into the deepest rooms of their home. In an anthill, passages and caves can go 3-4 meters deep. The harsher the winter is expected, the further the ants hide from the surface. In underground rooms, the temperature remains at levels from -1.5 to -2 degrees.
For diapause species, hibernation is such a natural and unchangeable event that even at home, with ideal stable temperature and humidity, with the arrival of autumn, ants stop their development and enter diapause.
In non-diapause species, if you dig up an anthill in winter, you can see that the insects do not sleep, but are in a slow state. They are not capable of attacking a trespasser, but instinctively secrete acid and swing their mandibles.
Bees, wasps, and termites also do not enter a state of diapause in winter. With the onset of autumn cold, they go deeper into their nests and hives. Insects tightly cover all entrances to their homes with leaves and other organic materials. They lead a semi-active lifestyle underground or in the depths of their nests.
When the ambient air temperature drops to +7 degrees, honey bees gather in a hive in a whole bunch, maintaining the temperature in it at a level of +15 to +25. They generate heat by contracting the pterygoid muscles on their backs. The bees located closer to the exits are replaced from time to time by others, and the frozen bees make their way deeper into the hive. All winter these bees feed on food stored since the summer.
Dragonflies spend the winter in the larval stage. They have gills that allow them to breathe dissolved oxygen in the water. They winter in water. In spring, the larva crawls out of the water onto the stem of the plant and after the last molt turns into an adult dragonfly.
Grasshopper eggs are not afraid of low temperatures. Before the onset of cold weather, grasshoppers safely hide their eggs in the soil. The grasshoppers themselves die in winter, and only the eggs survive the winter. This is their way to survive the winter.
Mosquitoes spend the winter in a state of diapause. Diapause can occur at the egg, larval or adult stages of the insect (imago). Each mosquito species has its own diapausing stage.
If mosquitoes overwinter in the stage of an adult insect (imago), then when they enter a state of diapause, the reproduction of females stops, the metabolic rate decreases and large fat reserves accumulate, due to which they live in the winter-spring period. Male mosquitoes, as a rule, do not hibernate and die in the fall after fertilizing females.
Most mosquitoes overwinter in the egg stage. At this stage, mosquitoes become most resistant to unfavorable environmental factors and, above all, to low winter temperatures. It is at the egg stage that most species of mosquitoes living in the northern regions overwinter.
Larval diapause also occurs in various genera of mosquitoes. The main feature of mosquito larval diapause is a delay in development and cessation of pupation.
Mosquitoes overwinter both in natural shelters (under bark, in dry grass, in the roots of trees, animal burrows, caves, etc.) and in artificial shelters (adits, vegetable stores, cellars, unheated outbuildings and basements, catacombs) . Most mosquitoes do not feed on blood in winter.
Ladybugs, as a rule, lead a solitary lifestyle and only before the onset of cold weather do they gather in large flocks. Flocks of ladybugs begin to fly from the meadows closer to the forest, closer to the trees, ravines to the banks of rivers. There, under the bark, in moss or under fallen leaves, they find their wintering place. They have no equal during this period in terms of the accumulation of individuals of the same species in one place. Once, scientists in such a colony counted about 40 million bugs!
Ladybugs overwinter in a state of diapause. In order not to turn into ice in the cold, they remove water from the body in the fall and take care of the production of natural antifreeze - they produce glycerin and sugar.
The wintering process occurs differently for each species of fly. Most often, the flies that we meet in our apartments are of the housefly species. It is known that the lifespan of an adult fly is about a month, but if the fly appears in the fall, then it hibernates during the winter cold. Before the onset of cold weather, female flies make their last clutches of eggs. However, those larvae that did not have time to turn into insects do not die, but fall asleep. They can survive almost any climatic conditions. Individuals that have recently turned into adults also fall asleep. With the onset of the first cold weather, flies hide in various cracks, window frames and other places where an even cool temperature is maintained throughout the winter period. Those flies that live in fields, vegetable gardens and orchards also hibernate. For their wintering they look for a place in the ground, but this very often does not save them from frost. Most flies die from the cold.
The surviving flies begin to come to life as the weather warms up. After a long winter hibernation, the fly at first walks as if sleepy, staggering from one side to the other. This is where the expression “sleepy as a fly” comes from. After some time, the insects get used to it and begin to live an ordinary normal life.
Character and lifestyle of the dragonfly
Dragonflies lead a solitary lifestyle, preferring to hunt on their own. Thanks to its specific wing structure, a dragonfly can either hover in the air, making an instant stop, or fly over vast distances, covering several hundred kilometers without rest.
During landing, the dragonfly does not fold its wings, like many other insects, but always leaves them in a straightened state.
The main peak of activity occurs during daylight hours, during which dragonflies fly in search of prey.
During hot hours, they can be observed in huge numbers along the banks of reservoirs and above forest edges.
The flight of a dragonfly is characterized by noiselessness, thanks to which the dragonfly can unnoticed approach its prey.
They can make intricate turns in the air, do somersaults and even fly backwards. Thanks to this ability, dragonflies can easily escape from predators pursuing them.
Origin of the species
Dragonflies are an ancient group of arthropods.
The first dragonflies lived on the planet back in the Carboniferous period during the Paleozoic era. The origin is related to the giant dragonfly-like insects Meganeura. Those, in turn, were large arthropods with a wingspan of up to 0.66 meters. They are considered the largest arthropods of that time. Subsequently, it was they who became the descendants of Kennedyina, Ditaxineurina, living already in the Triassic period of the Mesozoic. These arthropods were also distinguished by their large size, with a span of up to 90 mm. When the animals rested, the wings were hidden under the abdomen. Meganeura
In those days, insects had a well-developed trapping basket. They used it to grab victims. The next descendants of Meganeura living in the Jurassic period are Lestomorpha, Libellulomorpha, the larvae of which are capable of developing in water. Their aircraft has changed significantly, becoming more advanced. The descendants of meganeurinids gradually settled throughout the planet.
At this time, the descendants of the superfamily Calopterygoidea changed dramatically. Their wings became narrower and evened out in size. The Cretaceous era carried away many suborders of insects, and in the Cenozoic era modern suborders of dragonflies can be seen. In the Neocene, dragonflies ceased to differ from modern ones.
Types of dragonflies
Today there are about 5,000 species of dragonflies . The main varieties are divided into three orders:
- Homoptera, which include beauties, arrows and lute. They are incredibly light in weight.
- Heteropterans, which include such varieties as orthetrum, libellula, sympetrum and rockers. This species has a pair of hind wings with an expanded base, which serves as the name for this suborder.
- Anisozygoptera is a rare suborder, which is distributed exclusively in countries such as Nepal, Tibet and Japan. They combine the characteristics of both of the above suborders.
Beauty girl - lives mainly in the southern regions and regions with a subtropical climate.
The male and female dragonfly, beauty girl, differ from each other in color
Females of this species are able to descend directly into water to a depth of one meter to lay eggs, forming an air bubble around themselves.
They are found exclusively within clean water bodies, being a kind of indicator of their purity.
Fatima is a rare species listed in the Red Book. Inhabits areas of mountain rivers and streams along the sandy coast.
Dragonfly Fatima
Common Dedka is a species inhabiting the territory of modern Europe. It is also found in the Urals and around the Caspian Sea.
Dedka ordinary
The antlion is an insect similar to a dragonfly , although its flight is rather slow and its behavior is generally sluggish and unhurried.
The photo shows an antlion insect, which is often confused with a dragonfly
Reproduction of dragonflies
Before mating, the male performs a courtship dance in front of the female. Mating occurs in a rather interesting position. The male holds the female by the neck, and at this time the female attaches the end of her abdomen to the second segment of the male’s abdomen, into which sperm from the 9th segment is pumped. This type of mating in dragonflies is unique and almost never occurs in other insects.
The female lays up to several hundred eggs in one clutch. Eggs are laid in water. Subsequently, a larva emerges from the egg, whose development takes a long time, sometimes even up to 3 years. The larvae themselves are also predators and can even hunt tadpoles in the water. Very often, dragonfly larvae become prey for some species of fish, and therefore, out of hundreds of dragonfly larvae, only a few individuals survive.
From larva to adult dragonfly it can take from 7 to 11 molts, and an adult dragonfly can live from one to several months.
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Dragonfly nutrition
What does a dragonfly eat? Since it is a predator, the dragonfly feeds on insects . It grabs small insects with the help of serrated jaws in flight, and large ones with the help of tenacious legs.
In order to hunt large prey, a dragonfly has to descend to the surface of the earth and wait for prey while sitting on a blade of grass or a twig.
If a dragonfly notices its prey directly in flight, it will masterfully repeat the flight path of its prey, after which it will approach it as close as possible and make a sharp leap in order to grab it with its paws.
The structure of the dragonfly's jaws allows it to easily absorb even large prey.
The dragonfly eats its prey unusually quickly, since it is a very voracious insect.
In one day, she needs to consume an amount of food that significantly exceeds her own weight, so her daily diet consists of several dozen flies, mosquitoes and other insects.
Anatomy of a dragonfly
The dragonfly has a very recognizable appearance. Their abdomen is thin and elongated, round in shape, consisting of 11 segments. The head is movably connected to the chest, which gives her the ability to turn her head 180 degrees. Most of her head is occupied by her eyes, consisting of 30,000 small ocelli. Moreover, each such eye can work independently, independently of the others. In addition to these eyes, the dragonfly has 3 more simple eyes. They are arranged in a triangle and allow the insect to see what is happening behind and on the sides. The size of dragonflies varies greatly depending on the species. The smallest dragonfly is approximately 15 mm long, and the largest representative is approximately 10 cm in length.
Since the dragonfly is a very voracious predator, the insect’s mouth is armed with jagged jaws. The color of a dragonfly can be different - green, yellow, blue or light blue. The color can also be transparent. The dragonfly has two pairs of wings, their maximum span can reach 18 cm.
How long do dragonflies live?
Insects live for several months. Moreover, the entire development of dragonflies takes more than one year. The larvae that hatch under water live there from several months to four years. They evolve, hunt and hide from enemies. Gradually, dragonflies molt and grow, learning to fly. Adults leave water bodies and begin migration.
Dragonflies are special insects. They do not require pupae or cocoons to develop into adults. After emerging, the adult dragonfly dries out from the water for some time and begins its flight. A few hours after growing up, dragonflies begin hunting winged insects, gradually adapting to new conditions. At this stage of development, the insect is greatly influenced by the surrounding temperature and climate. In warm conditions without precipitation, dragonflies live up to six months, but in cold conditions they survive for several weeks.
Dragonfly protection
Photo: Dragonfly from the Red Book
Dragonflies have a very important role in the ecosystem. These insects destroy blood-sucking insects that carry various diseases. Dragonfly larvae provide food for many species of fish, and adult insects feed on birds, mammals and spiders.
In addition, dragonflies are excellent indicators of the environmental situation, since dragonfly larvae cannot develop in polluted water. Today, many species of these insects are listed in the International Red Book to track populations. They are taken under special protection.
A society for the protection of dragonflies has been created, which monitors the population of these insects. With the development of new territories by humans and the advent of urbanization, the dragonfly population began to decline. This is due to the draining of reservoirs by people, the construction of enterprises, roads and cities.
The dragonfly is a very beautiful and amazing insect. Watching these creatures is very entertaining. We must be more careful about the environment in order to preserve the diversity of these insect species.
Natural enemies of dragonflies
Photo: Blue dragonfly
The main enemies of dragonflies are:
- birds;
- predatory fish;
- orb-weaving spiders, hobo spiders and tetranatids;
- reptiles;
- carnivorous mammals.
Eggs and small larvae are eaten by fish, crustaceans, and other larvae. Most eggs die without hatching, they are eaten by predators, or unfavorable weather conditions prevent them from developing. In addition, dragonflies are often parasitized by sporozoans. Flukes, threadworms and water mites. Due to their lifestyle, dragonflies are also often preyed upon by insectivorous plants.
Dragonflies are very nimble insects that fly quite quickly. In the daytime, they can camouflage themselves under the glare of the sun, sitting on plants or trees with their belly down, their transparent wings are difficult to see by many predators, and this camouflage allows dragonflies to fool the enemy.
In addition, dragonflies fly masterfully, and it is very difficult to catch up with a dragonfly; the only option for a predator to feast on this insect is to take it by surprise. The larvae, protecting themselves from predators, try to burrow into the ground or hide in algae. Larvae swim very rarely, although they are very good at doing this.
