Nature endows its creations with many amazing properties, one of the most interesting and surprising is the glow. Fireflies, beetles from the family of the same name, have the characteristic property of emitting light. The largest number of species lives in tropical latitudes, but in the temperate zone beacons are lit at night. Ivanov worm, so they called an ordinary firefly in Russia. Females of this species invitingly honk with a greenish flashlight on their abdomen. In the darkness of the night, lonely lights can be seen on the edge, meadow or lake shore.

Morphological description of the species

The common firefly (Lampyrisnoctiluca) belongs to the order of beetles. The length of the imago is 12-18 mm. Insects are found throughout Europe and Asia. Sexual dimorphism is pronounced:

• Male - cigar-shaped body does not exceed 15 mm in size. The large head is covered by the pronotum. Eyes are hemispherical; antennae are short, filiform. The integument of the body is soft. The dark elytra are punctate. The wings are transparent, fold down on the back. The beetles are deprived of the oral apparatus, they do not feed, they live off the nutrients accumulated by the larval phase.
• The female is an elongated, flat body. Elytra and wings are reduced. Outwardly, insects look like larvae. Only females of the common firefly have the ability to glow bioluminescent. The light is created by an organ located in the last three segments of the abdomen. In this area, the body cover is translucent.

Interesting fact. The insect got its name "Ivanov worm" because of the Russian belief, according to which the firefly lights the first light on the holiday of Ivan Kupala (July 7).

Who does Ivanov worm shine for?

By night glow, sedentary females attract partners for mating. They cannot fly in search of active males, but they have found an interesting way to attract attention. Females sit on the ground or climb plants. The glow continues for two hours. If it is not possible to lure a partner, they continue to light the flame for 7-10 days. Males notice the glow when they are within 50 meters of an object. The peak of the mating season is observed in late June and early July.

Interesting fact. Males choose females with the brightest light on their abdomen. She is able to take out more eggs.

Fireflies are nocturnal; they choose forest glades, the shores of water bodies (lakes, rivers, streams) for habitation. Adults and larvae love moisture, and in addition, snails are found in such places - the favorite food of the descendants of the ivy worm. The best time to observe fireflies is from 10 pm to midnight. The radiance of insects should attract the attention of nocturnal predators, but frogs and reptiles do not touch them. This is due to the presence of poison in the body of fireflies.

Shine mechanism

A chemical reaction allows the organ to emit a greenish-yellow glow. The female Lampyrisnoctiluca has a group of special cells entangled with trachea for oxygen supply and nerve endings. The cells are filled with luciferin, a biological pigment that, when oxidized, produces light. The released energy is almost completely spent on glow, only 2% is on heat. Cells with uric acid crystals serve as reflectors of light waves. Larvae can also emit a glow, but to a lesser extent.

Information. Males of the common firefly often confuse the light of the waiting partner and the light of artificial lamps.

Reproduction

After mating, the females begin to ovipositor. In three days, they lay 50-100 eggs, placing them under the moss or in the tissue of the grass. Eggs 1 mm in diameter, light yellow, may glow. The embryo is visible through the thin shell. Having given life to their offspring, the adults die. After 2-3 weeks, the larvae appear. On their dark body, consisting of 12 segments, light spots are noticeable, which disappear with age. The head is small, the mandibles are sickle-shaped, and has a sucking canal. At the end of the abdomen there is a special brush for cleansing mucus from shellfish.

Predatory larvae feed on slugs and snails. The catch is several times larger than the size of the hunters. The larva bites the mollusc several times and injects the poison that liquefies the body. After a while, she drinks the nutritious substance. During development, the larvae molt 4-5 times. By winter, they huddle under stones and pupate. The pupa hibernates. In the spring, a beetle comes out of it.

The development of the larva can take several years. Cases of a decrease in the number of fireflies in different years associated with this factor have been recorded. Destruction of the habitat, pollution or drainage of water bodies, a large amount of artificial lighting leads to the death of insects.

Some insects have amazing glowing abilities. Their number is small and limited to only a few groups, such as collembolans, larvae of mushroom mosquitoes, and representatives of a number of families of the order Coleoptera. The ability to glow is most strongly developed in beetles. Fireflies are the most typical in this respect.

Fireflies are often distinguished into an independent family Lampyriclae. But more often they are still referred to as soft beetles. In total, about 2 thousand species of fireflies are known in the world fauna.

These really soft-bodied beetles are found mainly in the subtropics and tropics. Although they are all called fireflies, not every species has glowing organs. There are few among them who are active during the day. Naturally, they do not need luminiferous organs. Those that are active at night and have an amazing ability to glow, differ in character and, so to speak, glow mode. In some species, such organs are developed in both sexes, in others - only in females, in others - only in males.

Our fireflies, and there are 12 species of them on the territory of Russia and neighboring countries, are not much inferior to "tropical lamps": they give a rather strong light.

In most cases, the color of the light of beetles is dominated by blue and green tones. The light emitted by insects captures wavelengths from 486 to 656 nanometers. This area is small and very effective for the human eye. The release of heat during luminescence is negligible, and, for example, in pyrophores, 98% of the expended energy is converted into light. For comparison, let us recall that in ordinary incandescent bulbs, no more than 4% of the consumed electricity is utilized in the glow.

Scientists have spent a lot of effort to disassemble the structure of the luminescence organs and understand its mechanism. The luminous organ consists of a mass of multifaceted cells with very thin transparent walls, inside which there is a fine-grained mass. Air ducts branch in large numbers between such cells. The reason for the luminescence lies in the oxidation of the contents of these cells with oxygen, which the mentioned tubes deliver to them. The luminous organs also include the fatty body. It is believed that the luminescence of photogenic cells is associated with an oxidative process of an enzymatic nature: a special substance luciferin in the presence of the luciferase enzyme is oxidized into oxyluciferin. This process is accompanied by luminescence and is controlled by the nervous system.

The biological significance of the glow is not well understood. It is natural to assume that it serves to bring the sexes closer together. Or use a signal when food is found, since several individuals often gather for a meal at the same time. In most cases, the female shines stronger.

Subtropical species of fireflies are larger than ours and fly well. As a rule, beetles of both sexes emit light. Here is how A. Bram describes this spectacle: “These bugs gather in large groups on the banks of rivers overgrown with bushes. On a dark, moonless summer night, they are a delightful sight. They fly from place to place like sparkling sparks, but with the onset of morning they go out, and the worms themselves become invisible, hiding somewhere in the grass. "

Those who have been to the Black Sea coast of the Caucasus and have not limited themselves to visiting beaches and embankments may remember how in the evenings these amazing creatures flutter in the secluded alleys of parks and in shaded squares, periodically flashing, soundlessly like magic elves.

Adults and larvae of almost all fireflies are active and voracious predators: they feed on insects or molluscs, although they can attack both earthworms and caterpillars of moths. Some species develop under the bark and in the wood of decaying trees. Adults are often seen on flowers.

Spreading. Common firefly is common throughout the European part of Russia (except for the north), as well as in the Crimea, the Caucasus, Siberia and the Far East. About 100 years ago, he could often be found in Moscow, on the territory of the modern Neskuchny Garden. Here is a description of Neskuchny at a time when the garden belonged to Prince Shakhovsky: “From the middle of the bridge a pitchfork opened onto a gorge overgrown with forest, gloomy and deep. The hundred-year-old trees growing at the bottom look like trees. Their roots are washed by a barely noticeable stream that forms a small pond on the other side of the bridge. Numerous snakes are caught in the lard, bats are found, fireflies shine at night. " Unfortunately, now there is no hope of meeting this amazing insect in the center of Moscow. To do this, you should go to more distant places.

External signs. The common firefly is small in size; its body is flattened and covered with fine hairs. Looking at a dark brown female, you will never think that there is a beetle in front of you. It is inactive, completely devoid of wings and elytra and resembles a larva, from which it differs only in a wider chest plate. The head is completely hidden under the rounded cervical shield, the antennae are filiform. The luminous organs in the form of yellowish spots are located on the underside of the two penultimate segments of the abdomen. In the dark, they emit a bright greenish light. It is interesting that the eggs laid by the female at first also emit a dim glow, but soon this light dies out.

The common firefly larva has a very small head. The last segment of the abdomen bears a retractable brush, consisting of a double ring of cartilaginous rays. With its help, the larva reads mucus and earth particles from its body. This is absolutely necessary for her, since she feeds (as, incidentally, adults also often) on slugs and snails, abundantly covered with mucus.

Lifestyle. Mating takes place on the soil surface or on short plants and often lasts 1 to 3 hours. The female is capable of laying up to 100 eggs. She hides them in the depressions of the soil, in moss or in various debris.

The development and feeding of the larvae emerging from them lasts for several months. At the larval stage, the firefly usually hibernates. The pupa forms in the soil in spring. After a week or two, a beetle emerges from it. The entire life cycle of a firefly lasts 1 to 2 years.

Some authors write that when disturbed, fireflies stop glowing. My personal experience with an ordinary firefly does not allow me to agree with such a statement. Somehow I needed to find several copies of these beetles for photography. Attempts to find them in the near Moscow region were unsuccessful. Neither my friends and acquaintances, nor I myself have ever met them here. But he who seeks will always find! Our meeting took place on a forest edge at a dark June midnight in the Yaroslavl region. (By the way, the popular name of the firefly Ivanov worm is probably explained by the fact that it is most often found at the end of June, when Midsummer's Day was widely celebrated in Russia - Ivan Kupala).

Several days before that there was a sweltering heat, which, as it should be at this time, ended one day with a thunderstorm. After this thunderstorm, I walked through the forest from the highway to my village. And so, crossing a small field overgrown with young birch forests, over which small white clouds of vapor were hovering like ghosts, suddenly I saw bright lights in the grass. Fireflies! Of course it was them. It's good that I had a flashlight with me. Otherwise it would be difficult to collect them. Immediately taking off my backpack, I set about packing. The light from the female was not enough to illuminate her. I squatted down near the luminous point, carefully parted the grass and directed the beam of the flashlight at it. Here the whole slightly crooked larva-like wingless female was visible. She tenaciously held on to a blade of grass with her legs, clearly not wanting to part with it. Indeed, waiting was her lot. Waiting for a gentleman. There were also males around some of the females - slender, I would say, elegant beetles, equipped with full-fledged elytra. This was especially helpful, since I needed both sexes. It would be simply impossible to find males without females: after all, although they have organs of luminescence, they practically do not emit light. Of the fairly large number of beetles that are glowing around, I have selected only a few pairs and placed them in a jar. At the same time, the males did not show the slightest desire to escape from my fingers and fly away. I knew that although they were winged, they rarely and reluctantly fly.

That night, I established that those who believe that disturbed fireflies stop emitting light are wrong. During my hunt, some females fell to the ground. But they did not stop glowing for a moment, which made it easier to find them in the grass. Moreover, the glow continued even after the caught beetles ended up in a glass jar. They glowed inside her for a long time and on the way home and at home. In total darkness, 5 - 6 females emitted enough light to make out the text of a book held up to this amazing lamp.

Role in nature. The common firefly is a very characteristic inhabitant of woodland, inhabiting forest edges, meadows, roadsides, the shores of lakes and streams. Here, in damp places, he easily finds his main food - terrestrial mollusks, which he destroys in abundance.

N.Yu. FEOKTISTOVA

“... at first only two or three green dots were blinking there, gliding smoothly among the trees.
But gradually there were more of them, and now the whole grove is illuminated by a fantastic green glow.
We have never seen such a huge cluster of fireflies.
They ran like a cloud among the trees, crawled over the grass, bushes and trunks ...
Then sparkling streams of fireflies floated over the bay ... "
J. Darrell. "My family and other animals"

Probably everyone has heard about fireflies. Many have seen them. But what do we know about the biology of these amazing insects?

Fireflies, or fireflies, are representatives of a separate family Lampyridae in the order of beetles. In total, there are about 2000 species, and they are distributed almost all over the world. The sizes of different types of fireflies range from 4 to 20 mm. The males of these beetles have a cigar-shaped body and a rather large head with large hemispherical eyes and short antennae, as well as very reliable and strong wings. But female fireflies are usually wingless, soft-bodied and resemble larvae in their appearance. True, in Australia there are species in which wings are developed in both males and females.

All types of fireflies have the amazing ability to emit soft phosphorescent light in the dark. Their organ of luminescence - the photophore - is most often located at the end of the abdomen and consists of three layers. The lower layer acts as a reflector - the cytoplasm of its cells is filled with microscopic crystals of uric acid that reflect light. The upper layer is represented by a transparent, light-transmitting cuticle - in a word, everything is like in an ordinary lantern. The photogenic cells themselves, which produce light, are located in the middle layer of the photophore. They are densely entwined with trachea, through which air is supplied with the oxygen necessary for the reaction, and contain a huge number of mitochondria. Mitochondria produce the energy necessary for the oxidation of a special substance, luciferin, with the participation of a corresponding enzyme, luciferase. The visible result of this reaction is bioluminescence - luminescence.

The efficiency of firefly flashlights is unusually high. If in an ordinary light bulb, only 5% of the energy is converted into visible light (and the rest is dissipated in the form of heat), then from 87 to 98% of the energy of fireflies goes into light rays!

The light emitted by these insects belongs to a rather narrow yellow-green region of the spectrum and has a wavelength of 500-650 nm. There are no ultraviolet and infrared rays in the bioluminescent light of fireflies.

The glowing process is under nervous control. Many species are capable of increasing and decreasing the intensity of light at will, as well as emitting intermittent light.

Both males and females of fireflies possess a luminous organ. Moreover, the larvae, pupae, and even the eggs laid by these beetles glow, although much weaker.

The light emitted by many tropical firefly species is very bright. The first Europeans to settle in Brazil, in the absence of candles, lit their homes with fireflies. They also filled the icon lamps in front of the icons. Indians, traveling through the jungle at night, still tie large fireflies to their toes. Their light not only helps to see the road, but, possibly, scares away snakes.

Entomologist Evelyn Chisman wrote in 1932 that some eccentric ladies in South America and the West Indies, where especially large fireflies are found, adorned their hair and dresses with these insects before the evening holidays, and their living ornaments sparkled like diamonds.

You and I cannot admire the glow of bright tropical species, but fireflies also live in our country.

Our most common large firefly (Lampyris noctiluca) is also known as the Ivanov worm. This name was given to the female of this species, which has an elongated wingless body. It is her rather bright flashlight that we usually notice in the evenings. Males of Ivan's worm are small (about 1 cm) brown beetles with well-developed wings. They also have glowing organs, but you can usually notice them only by taking the insect in your hands.

In the book by Gerald Durrell, the lines from which are taken as an epigraph to our article, most likely the flying firefly Luciola mingrelica is mentioned, which is found not only in Greece, but also on the Black Sea coast (including in the Novorossiysk region), and often suits there are similar fantastic performances.

And in Primorye, you can find a rare and poorly studied firefly pyrocelium (Pyrocaelia rufa). Both males and females of this species glow actively on dark August nights.

It is believed that the bioluminescence of fireflies is a means of inter-sex communication: by light signals, partners let each other know about their location. And if our fireflies glow with a constant light, then many tropical and North American forms flash their lanterns, and in a certain rhythm. Some species perform real serenades for their partners, moreover choral ones, flashing and fading in unison with the whole flock gathered on one tree.

And the beetles, located on the neighboring tree, also flare up in concert, but not in time with the fireflies sitting on the first tree. Also, in their own rhythm, bugs glow on other trees. Eyewitnesses say that this spectacle is so bright and beautiful that it overshadows the illumination of large cities.

Hour after hour, weeks and even months, the bugs blink on their trees in the same rhythm. Neither wind nor heavy rain can change the intensity and frequency of flares. Only the bright light of the moon can dim these unique natural lanterns for a while.

It is possible to disrupt the synchronicity of the flashes by illuminating the tree with a bright lamp. But when the outside light goes out, the fireflies start blinking again, as if on command. First, those in the center of the tree adapt to one rhythm, then neighboring beetles connect to them and gradually waves of lights flashing in unison spread throughout all the branches of the tree.

Males of different types of fireflies fly in search of flashes of a certain intensity and frequency - signals emitted by a female of their own kind. As soon as huge eyes catch the required light password, the male descends next to it, and the beetles, shining with lights for each other, perform the sacrament of marriage. However, this idyllic picture can sometimes be violated in the most nightmarish way due to the fault of females of some species belonging to the genus Photuris. These females emit signals that attract males of other species. And then they just eat them. This phenomenon is called aggressive mimicry.

But if no tragedies occur and beetles of the same species find each other, then after the mating ceremony, the female lays eggs, from which rather gluttonous larvae emerge, the favorite food of many of which are snails and slugs. With their powerful mandibles, the larvae of fireflies not only bite through the integuments of snails, but also inject paralyzing poison into their bodies. Then they calmly devour the prey. For example, in Japan, the larvae of the water firefly (Luciola cruciata) are quite common in rice fields. They live in water or wet silt and are clearly visible at night due to the bright blue glow. These larvae are very useful in that they eat gastropods, which are intermediate hosts for various flukes.

The grown larva is taken under stones or under the bark of trees and pupates there. The pupa survives the winter, and in the spring a new firefly emerges from it, ready to delight the world around it with its amazing spark ...

A firefly is an insect that belongs to the order coleoptera (or beetles), a suborder of common beetles, the family of fireflies (lampirids) (Latin Lampyridae).

Fireflies get their name from the ability of their eggs, larvae, and adults to glow. The earliest written records of fireflies are records in a Japanese poetry collection of the late 8th century.

Firefly - description and photo. What does a firefly look like?

Fireflies are small insects ranging in size from 4 mm to 3 cm. Most of them have a flattened elongated body, covered with hairs, and a structure characteristic of all beetles, in which they stand out:

• 4 wings, two of the upper ones turned into elytra, punctate and sometimes with traces of ribs;

• mobile head, decorated with large faceted eyes, fully or partially covered by the pronotum;

• filiform, comb or sawtooth antennae, 11-segmented;

• the gnawing mouth apparatus (more often it is observed in larvae and females; in adult males it is reduced).

Males of many species, similar to common beetles, are very different from females, more like larvae or small worms with legs. Such representatives have a dark brown body on 3 pairs of short limbs, simple large eyes and have no wings and elytra at all. Accordingly, they cannot fly. Their antennae are small, consisting of three segments, and the hard-to-see head is hidden behind the cervical shield. The less developed the female, the more she glows.

Fireflies are not brightly colored: representatives of a brown color are more common, but their covers can also contain black and brown tones. These insects have relatively soft and flexible, moderately sclerotized body integuments. Unlike other beetles, firefly elytra are very light; therefore, insects were previously classified as soft beetles (Latin Cantharidae), but then they were isolated into a separate family.

Why are fireflies glowing?

Most members of the firefly family are known for their ability to emit a phosphorescent glow that is especially noticeable in the dark. In some species, only males can glow, in others - only females, in others - both of them (for example, Italian fireflies). Males emit bright light in flight. Females are inactive and usually glow brightly on the soil surface. There are also fireflies that do not have this ability at all, while in many species the light comes even from larvae and eggs.

By the way, few animal sushi generally exhibit the phenomenon of bioluminescence (chemical luminescence). Known capable of this larvae of mushroom mosquitoes, springtails (collembolans), fire flies, jumping spiders and representatives of beetles, for example, such as fire-carrying clickers (pyrophoruses) from the West Indies. But if you count the marine life, then there are at least 800 species of luminous animals on Earth.

The organs that allow fireflies to emit rays are photogenic cells (lanterns), abundantly entwined with nerves and trachea (air ducts). Outwardly, lanterns look like yellowish spots on the underside of the abdomen, covered with a transparent film (cuticle). They can be located on the last segments of the abdomen or evenly distributed over the body of the insect. Beneath these cells lie others filled with uric acid crystals and capable of reflecting light. Together, these cells work only if there is a nerve impulse from the insect's brain. Oxygen enters the photogenic cell through the trachea and, with the help of the luciferase enzyme, which accelerates the reaction, oxidizes the compound of luciferin (a light-emitting biological pigment) and ATP (adenosine triphosphoric acid). Thanks to this, the firefly glows, emitting light blue, yellow, red or green. Males and females of the same species most often emit rays of a similar color, but there are exceptions. The color of the glow depends on the temperature and acidity (pH) of the environment, as well as on the structure of the luciferase.

Beetles regulate the glow themselves; they can intensify or weaken it, make it intermittent or continuous. Each species has its own unique phosphoric radiation system. Depending on the target, the glow of the firefly beetles can be pulsating, flashing, stable, fading, bright, or dim. The female of each species reacts only to the signals of the male with a certain frequency and intensity of light, that is, his mode. With a special rhythm of light emission, beetles not only attract partners, but also scare away predators and guard the borders of their territories. Distinguish:

• search and calling signals in males;
• signals of consent, refusal and post-copulatory signals in females;
• signals of aggression, protest and even light mimicry.

Interestingly, fireflies spend about 98% of their energy on emitting light, while an ordinary light bulb (incandescent lamp) converts only 4% of the energy into light, the rest of the energy is dissipated in the form of heat.

Daytime fireflies often do not need the ability to emit light, so they do not have it. But those daytime representatives who live in caves or in the dark corners of the forest also turn on their "flashlights". The eggs of all kinds of fireflies also emit light at first, but soon it dies out. During the day, the light of the firefly can be seen if you cover the insect with two palms or move it to a dark place.

By the way, fireflies also send signals using the direction of flight. For example, representatives of one species fly in a straight line, representatives of another species fly along a broken line.

Types of firefly light signals.

V.F.Bak divided all light signals of fireflies into 4 types:

• Continuous glow

This is how adult beetles belonging to the genus Phengodes glow, and the eggs of all fireflies, without exception. Neither external temperature nor lighting affects the brightness of the rays of this uncontrollable type of glow.

• Intermittent glow

Depending on environmental factors and the internal state of the insect, it can be weak or strong light. It can fade completely for a while. This is how most larvae shine.

• Ripple

This type of glow, in which periods of emission and absence of light are repeated at regular intervals, is characteristic of the tropical genera Luciola and Pteroptix.

• Outbreaks

There is no time dependence between the intervals of flares and their absence with this type of glow. This type of signal is typical for most fireflies, especially in temperate latitudes. In this climate, the ability of insects to emit light is highly dependent on environmental factors.

HA. Lloyd also identified a fifth type of glow:

• Flicker

This type of light signal is a series of short flashes (frequency from 5 to 30 Hz), appearing immediately after each other. It is found in all subfamilies, and its presence does not depend on the place and environment.

Firefly communication systems.

Lampirids have 2 types of communication systems.

1. In the first system, an individual of the same sex (usually a female) emits specific calling signals and attracts a representative of the opposite sex, for whom the presence of its own light organs is not required. This type of communication is typical for fireflies of the genera Phengodes, Lampyris, Arachnocampa, Diplocadon, Dioptoma (Cantheroidae).
2. In the system of the second type, individuals of the same sex (usually flying males) emit calling signals, to which flightless females give sex- and species-specific responses. This mode of communication is characteristic of many species from the subfamilies Lampyrinae (genus Photinus) and Photurinae in the Americas.

This division is not absolute, since there are species with an intermediate type of communication and with a more perfect dialogue system of luminescence (in the European species Luciola italica and Luciola mingrelica).

Synchronous flashing of fireflies.

In the tropics, many species of bugs from the Lampyridae family seem to shine together. They simultaneously light up their "flashlights" and extinguish them at the same time. Scientists called this phenomenon a synchronous flashing of fireflies. The process of synchronous flashing of fireflies has not yet been fully understood, and there are several versions of how insects manage to shine at the same time. According to one of them, within a group of beetles of the same species there is a leader, and he serves as the conductor of this "chorus". And since all representatives know the frequency (break time and glow time), they manage to do it very amicably. Mainly, male lampirids flare up simultaneously. Moreover, all researchers are inclined to believe that the synchronization of firefly signals is associated with the sexual behavior of insects. By increasing the population density, they increase the ability to find a mating partner. Also, scientists have noticed that the synchronicity of the light of insects can be violated if you hang a lamp next to them. But with the termination of its work, the process is restored.

The first mention of this phenomenon dates back to 1680 - this is a description made by E. Kampfer after his trip to Bangkok. Later, many statements were made about the observation of this phenomenon in Texas (USA), Japan, Thailand, Malaysia and the mountainous regions of New Guinea. Especially many of these types of fireflies live in Malaysia: there this phenomenon is called "kelip-kelip" by the locals. In the United States, in the Elcomont National Park (Great Smoky Mountains), visitors observe the synchronized glow of representatives of the species Photinus carolinus.

Where do fireflies live?

Fireflies are quite common, heat-loving insects that live in all parts of the world:

• in the Americas;
• in Africa;
• in Australia and New Zealand;
• in Europe (including the UK);
• in Asia (Malaysia, China, India, Japan, Indonesia and the Philippines).

Most fireflies are found in the Northern Hemisphere. Many of them live in warm countries, that is, in the tropical and subtropical regions of our planet. Some species are found in temperate latitudes. In Russia, 20 species of fireflies live, which can be found throughout the territory, except for the north: in the Far East, in the European part and in Siberia. They can be found in deciduous forests, in swamps, near rivers and lakes, in glades.

Fireflies do not like to live in groups, they are loners, but at the same time they often form temporary clusters. Most of the fireflies are nocturnal animals, but there are some that are active during daylight hours. During the day, insects rest on the grass, hide under bark, stones or in silt, and at night those that are able to fly do it smoothly and quickly. In cold weather, they can often be seen on the surface of the earth.

What do fireflies eat?

Both larvae and adults are more often predators, although there are fireflies that feed on nectar and pollen from flowers, as well as rotting plants. Carnivorous bugs prey on other insects, caterpillars of butterflies, molluscs, millipedes, earthworms, and even their fellows. Some females living in the tropics (for example, from the genus Photuris), after mating, imitate the rhythm of the glow of males of another species in order to eat them and get nutrients for the development of their offspring.

Females in adulthood feed more often than males. Many males do not eat at all and die after several mates, although there is other evidence that all adults eat food.

The firefly larva has a retractable brush on the last segment of the abdomen. She is needed in order to clean off the mucus remaining on her small head after eating snails and slugs. All firefly larvae are active predators. They mainly eat shellfish and often settle in their hard shells.

Reproduction of fireflies.

Like all coleoptera, fireflies develop with complete metamorphosis. The life cycle of these insects consists of 4 stages:

1. Egg (3-4 weeks),
2. Larva, or nymph (from 3 months to 1.5 years),
3. Pupa (1-2 weeks),
4. Imago, or an adult (3-4 months).

Females and males mate on the ground or on low plants for 1-3 hours, after which the female lays up to 100 eggs in depressions in the soil, in garbage, on the lower surface of leaves or in moss. The eggs of common fireflies look like pearlescent yellow pebbles washed with water. Their shell is thin, and the "head" side of the eggs contains the embryo, which is visible through a transparent film.

After 3-4 weeks, ground or aquatic larvae hatch from the eggs, which are voracious predators. The body of the larvae is dark, slightly flattened, with long running legs. In aquatic species, lateral abdominal gills are developed. Small elongated or square head of nymphs with three-segmented antennae is strongly retracted into the prothorax. On the sides of the head there is 1 light eye. Strongly sclerotized mandibles (mandibles) of larvae have the shape of a sickle, inside which there is a sucking channel. Unlike adult insects, nymphs have no upper lip.

The larvae settle on the surface of the soil - under stones, in the forest floor, in the shells of mollusks. Nymphs of some species of fireflies pupate in the same autumn, but they mostly survive the winter and only in the spring turn into pupae. The larvae pupate in the soil or by hanging themselves on the bark of a tree, as caterpillars do. After 1-2 weeks, beetles crawl out of the pupae.

The general life cycle of fireflies lasts 1-2 years.

Types of fireflies, photos and names.

In total, entomologists count about 2,000 species of fireflies. Let's talk about the most famous of them.

• Common firefly ( he is great firefly) (Latin Lampyris noctiluca) has the popular names of Ivanov worm or Ivanovsky worm. The appearance of the insect was associated with the holiday of Ivan Kupala, because it is with the arrival of summer that the mating season begins for fireflies. Hence the popular nickname appeared, which was given to the female, very similar to the worm. The large firefly is a beetle with the characteristic appearance of fireflies. The size of males reaches 11-15 mm, females - 11-18 mm. The insect has a flat villous body and all the other signs of the family and order. The male and female of this species are very different from each other. The female is similar to a larva and leads a sedentary, ground-based way of life. Both sexes have the ability to bioluminescence. But in the female, this is much more pronounced, at dusk she emits a rather bright glow. The male flies well, but glows very weakly, almost imperceptible to observers. Obviously, it is the female who gives the signal to the mate.

• Water firefly (lat.Luciola cruciata)- a common inhabitant of the rice fields of Japan. Lives only in wet silt or directly in water. It hunts at night for mollusks, including intermediate hosts of fluke worms. During the hunt, it shines very brightly, emitting a blue light.

• Common oriental firefly (fire photinus) (lat.Photinus pyralis) lives in North America. Males from the genus Photinus glow only on takeoff and fly in a zigzag path, while females use imitative illumination to eat males of other species. From representatives of this genus, American scientists isolate the enzyme luciferase in order to use it in biological practice. The common oriental firefly is the most common in North America. It is a nocturnal beetle with a dark brown body 11-14 mm long. Thanks to the bright light, it is clearly visible on the soil surface. Females of this species are similar to worms. Fire photinus larvae live from 1 to 2 years and hide in humid places - next to streams, under bark and on the ground. They spend the winter buried in the ground. Both adult insects and their larvae are predators, eating worms and snails.

• Pennsylvanian firefly (lat.Photuris pennsylvanica) lives only in Canada and the USA. An adult beetle reaches a size of 2 cm. It has a flat black body, red eyes and yellow underwings. Photogenic cells are located on the last segments of its abdomen. The larva of this insect was nicknamed "the luminous worm" for its ability to bioluminescence. The worm-like females of this species also have the ability to mimic light, they mimic the signals of the Photinus firefly species to grab and eat their males.

• Cyphonocerus ruficollis- the most primitive and poorly studied species of fireflies. It lives in North America and Eurasia. In Russia, the insect is found in Primorye, where females and males actively glow in August. The beetle is included in the Red Book of Russia.

• Ginger firefly (pyrocelia firefly) (lat.Pyrocaelia rufa)- a rare and poorly studied species inhabiting the Russian Far East. Its length can be up to 15 mm. It is called a red firefly because its scutellum and rounded pronotum have an orange tint. The elytra of the beetle is dark brown, the antennae are saw-shaped and small. The larval stage of this insect lasts 2 years. You can find the larva in the grass, under stones, or in the forest floor. Adult males fly and glow.
• Fir firefly (Latin Pterotus obscuripennis)- a small black beetle with an orange head and saw-like antennae (bunches). Females of this species fly and glow, while males lose their ability to emit light after becoming an adult insect. Fir fireflies live in the forests of North America.

• Central European worm (glow worm) (Latin Lamprohiza splendidula)- an inhabitant of the center of Europe. There are clear transparent spots on the pronotum of the male beetle, and the rest of its body is colored light brown. The body length of the insect varies from 10 to 15 mm. Males glow especially brightly in flight. Females are worm-like and are also capable of emitting bright light. The organs of light production are located in Central European worms not only at the end of the abdomen, but also in the second segment of the chest. Larvae of this species can also glow. They have a black villous body with yellow-pink dots on the sides.

Living radiance

“... at first only two or three green dots were blinking there, gliding smoothly among the trees.
But gradually there were more of them, and now the whole grove is illuminated by a fantastic green glow.
Never before have we seen such a huge cluster of fireflies.
They ran like a cloud among the trees, crawled over the grass, bushes and trunks ...
Then sparkling streams of fireflies floated over the bay ... "

J. Darrell. "My family and other animals"

Probably everyone has heard about fireflies. Many have seen them. But what do we know about the biology of these amazing insects?

Fireflies, or fireflies, are members of a separate family Lampyridae in the detachment of beetles. In total, there are about 2000 species, and they are distributed almost all over the world. The sizes of different types of fireflies range from 4 to 20 mm. The males of these beetles have a cigar-shaped body and a rather large head with large hemispherical eyes and short antennae, as well as very reliable and strong wings. But female fireflies are usually wingless, soft-bodied and resemble larvae in their appearance. True, in Australia there are species in which wings are developed in both males and females.

All types of fireflies have the amazing ability to emit soft phosphorescent light in the dark. Their organ of luminescence is photophore- most often located at the end of the abdomen and consists of three layers. The lower layer acts as a reflector - the cytoplasm of its cells is filled with microscopic crystals of uric acid that reflect light. The upper layer is represented by a transparent, light-transmitting cuticle - in a word, everything is like in an ordinary lantern. The photogenic cells themselves, which produce light, are located in the middle layer of the photophore. They are densely entwined with trachea, through which air is supplied with the oxygen necessary for the reaction, and contain a huge number of mitochondria. Mitochondria produce the energy necessary for the oxidation of a special substance, luciferin, with the participation of a corresponding enzyme, luciferase. The visible result of this reaction is bioluminescence - luminescence.

The efficiency of firefly flashlights is unusually high. If in an ordinary light bulb, only 5% of the energy is converted into visible light (and the rest is dissipated in the form of heat), then from 87 to 98% of the energy of fireflies goes into light rays!

The light emitted by these insects belongs to a rather narrow yellow-green region of the spectrum and has a wavelength of 500-650 nm. There are no ultraviolet and infrared rays in the bioluminescent light of fireflies.

The glowing process is under nervous control. Many species are capable of increasing and decreasing the intensity of light at will, as well as emitting intermittent light.

Both males and females of fireflies possess a luminous organ. Moreover, the larvae, pupae, and even the eggs laid by these beetles glow, although much weaker.

The light emitted by many tropical firefly species is very bright. The first Europeans to settle in Brazil, in the absence of candles, lit their homes with fireflies. They also filled the icon lamps in front of the icons. Indians, traveling at night through the jungle, still tie large fireflies to their thumbs. Their light not only helps to see the road, but, possibly, scares away snakes.

Entomologist Evelyn Chisman wrote in 1932 that some eccentric ladies in South America and the West Indies, where especially large fireflies are found, adorned their hair and dresses with these insects before the evening holidays, and their living ornaments sparkled like diamonds.

You and I cannot admire the glow of bright tropical species, but fireflies also live in our country.

Our most common big firefly(Lampyris noctiluca) is also known as “ ivanov worm ". This name was given to the female of this species, which has an elongated wingless body. It is her rather bright flashlight that we usually notice in the evenings. Males of Ivan's worm are small (about 1 cm) brown beetles with well-developed wings. They also have glowing organs, but you can usually notice them only by picking up the insect.

In the book by Gerald Durrell, the lines from which are taken as an epigraph to our article, it is most likely mentioned flying firefly -Luciola Mingrelik beetleLuciola mingrelica, found not only in Greece, but also on the Black Sea coast (including in the Novorossiysk region), and often arranges similar fantastic performances there.

Photinus pyralis in flight

And in Primorye, you can find a rare and poorly studied firefly pyrocelium(Pyrocaelia rufa). Both males and females of this species glow actively on dark August nights.

In Japan live Luciola parva and Luciola vitticollis.

It is believed that the bioluminescence of fireflies is a means of inter-sex communication: partners let each other know about their location with light signals. And if our fireflies glow with a constant light, then many tropical and North American forms flash their lanterns, and in a certain rhythm. Some species perform real serenades for their partners, moreover choral ones, flashing and fading in unison with the whole flock gathered on one tree.

And the beetles, located on the neighboring tree, also flare up in concert, but not in time with the fireflies sitting on the first tree. Also, in their own rhythm, bugs glow on other trees. Eyewitnesses say that this spectacle is so bright and beautiful that it overshadows the illumination of large cities.

Hour after hour, weeks and even months, the bugs blink on their trees in the same rhythm. Neither wind nor heavy rain can change the intensity and frequency of flares. Only the bright light of the moon can dim these unique natural lanterns for a while.

It is possible to disrupt the synchronicity of the flashes by illuminating the tree with a bright lamp. But when the outside light goes out, the fireflies start blinking again, as if on command. First, those in the center of the tree adapt to one rhythm, then neighboring beetles connect to them and gradually waves of lights flashing in unison spread throughout all the branches of the tree.

Males of different types of fireflies fly in search of flashes of a certain intensity and frequency - signals emitted by a female of their own kind. As soon as huge eyes catch the required light password, the male descends beside, and the beetles, shining with lights for each other, perform the sacrament of marriage. However, this idyllic picture can sometimes be disturbed in the most nightmarish way due to the fault of females of some species belonging to the genus Photuris... These females emit signals that attract males of other species. And then they just eat them. A similar phenomenon is called aggressive mimicry.