Order Copepoda crustaceans. Cyclops crustaceans: structure, nutrition, coloring, reproduction, breeding, significance for humans, interesting facts, representatives, photos

Which is why they got their name. The antennae of Cyclops are short, and the antennae used for swimming are single-branched. They don't have a heart. About 250 species are known, distributed throughout to the globe. They usually live at the bottom of freshwater reservoirs, and only a few live in the water column. Cyclops are predators and feed on protozoa, rotifers, and small crustaceans. They themselves serve as food for many fish and fry. Can serve intermediate hosts parasitic worms (guinea worm, broad tapeworm and others).

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Cyclops Cyclops Scientific classification Kingdom: Animals Type ... Wikipedia

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Cyclops (Cyclopidae), family of copepods. Body length 1–5.5 mm. There is an unpaired frontal ocellus (hence the name). The antennules are short, the antennae are single-branched (used for swimming), the abdomen is longer than the cephalothorax, in females with two eggs... ...

I Cyclops see Cyclops. II Cyclops (Cyclopidae) family of copepods (See Copepods). Body length 1 5.5 mm. There is an unpaired frontal ocellus (hence the name). The antennas are short, single-branched antennas (serve for... ... Great Soviet Encyclopedia

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Subfamily Eucyclopinae
This includes cyclops that inhabit ponds and other small bodies of water, the littoral part of reservoirs and lakes. Their favorite biotype is the zone of thickets of coastal aquatic vegetation. Representatives of this family are usually absent in the non-lagal zone of large reservoirs. In rivers they are found in the coastal part. Animals lead a benthic lifestyle (climbing on macrophytes and substrate), especially characteristic of representatives of the genera Ectocyclops and Paracyclops. In this regard, the body of Cyclops is greatly flattened in the dorsal-abdominal part, and the antennae are shortened. In the reservoirs of Moldova, the subfamily includes nine species and three subspecies. Most widespread one is different.

Eucyclops serrulatus - Eucyclops serrulatus
It is characterized by the presence of a group of small hairs on the sides of the last thoracic segment, a thin abdomen, the structure of the genital segment and the receptaculum seminis. The genital segment, for example, in the anterior section, is greatly expanded, in the posterior section it is almost cylindrical. The spermatheca consists of two wide sections, connected in the middle part by a narrow duct. The outer edges of the furcal branches are equipped with a number of small, clearly visible sawtooth spines. They usually do not reach the base of the branches.
A characteristic feature of the species is the presence of a subulate seta on the outer edge of the furca. The middle apical setae are well developed.
The anterior antennae are 12-segmented and short; the three distal segments are very long and thin. The legs of the fifth pair are made in the form of an angular plate bearing a powerful knife-like spike on the inside. The color of the cyclops is usually straw-yellow, sometimes brown.
The female's egg sacs are strongly divergent and elongated-oval. The male is distinguished by the absence of spines on the outer edge of the furca.
The length of the female is 0.8-1.5, the male – 0.6-0.8 mm. E. serrulatus forms two varieties - proximus and speratus. From typical shape they differ in the structure of the furcal branches and the armament of their outer edge. Both varieties are found in the reservoirs of Moldova.
E. serrulatus can reliably be classified as cosmopolitan. It lives in Europe, Asia, North America, New America. Zealand and Africa. In the USSR it is distributed within all landscape zones, from the Arctic islands, Far East, mountain reservoirs of the Caucasus to steppe and lowland reservoirs of the European part and Central Asia. Benthic species. Inhabits the most diverse and flowing water bodies, in thickets of aquatic micro- and macrophytes, avoiding open places with strong currents. Found in ground spring waters, as well as caves and deep wells.
This crustacean is eurythermic. The amplitude of its adaptability to temperature changes is very wide: 4-30°C. The boundaries of optimal development of the species are 6-25°C. In relation to the degree of water mineralization, E. serrulatus shows itself to be highly euryhaline. Common in reservoirs with a pH of 4.6-9.8. They are not found in dystrophic reservoirs with a pH below 4.5. However, a change in pH to the alkaline side causes a sharp reduction in the fertility of this species.
In Moldova it is found in a wide variety of water bodies, often year-round. Does not achieve high quantitative indicators of development. In small reservoirs its abundance ranges from 4.0-10.0, Lake Cahul - 18.0-22.0, left-bank tributaries of the Prut - 0.5 thousand specimens/m?. Its density is somewhat higher in the Yagorlyk creek - 3.5-6.2 thousand specimens/m?. In the Dubossary Reservoir, the crustacean is rare (3.0 thousand specimens/m?).
The number of litters in E. serrulatus varies widely depending on the temperature of the habitat, the amount of food and its composition, the age of the female, etc. For example, at 13°C a female Cyclops makes up to 28, at 17°C – 38, and at 20 °C – 60 clutches ( total quantity eggs - 1270, 1489 and 2248 pcs. respectively). The same relationship has been established regarding the embryonic development of the crustacean. At a temperature of 16°C it lasts four days, and at 30°C - one day. During fasting, the number of clutches is reduced from 24 to 14. B optimal conditions nutrition in a clutch averages 38.6-39.4 eggs, during fasting - 23.5 and below, down to zero.
The individual fertility of a female varies between 25-60 eggs. The number of eggs in egg sacs is rarely the same. E. serrulatus reaches sexual maturity at a water temperature of 18-20°C on the 15-16th day of life. The nauplial period under these conditions lasts three to four, and the copepodite period lasts five days. The total lifespan of a Cyclops is 44-57 days. The average length of newborn nauplii is 0.088, the daily increase is 0.020 mm.
Cyclops is included in the food spectrum of juveniles and older age groups fish feeding in coastal zone among macrophytes.

Subfamily Cyclopidae
Within Moldova it is represented by four genera (Eucyclops, Acanthocyclops, Cyclops, Mesocyclops),
21 species and one subspecies. Cyclops, belonging to this subfamily, are clearly distinguishable due to the absence of a group of setae on the sides of the last thoracic segment and a sawtooth row of spines on the outer edge of the furcal rami. The armament of the distal segment of the fifth pair of legs consists of two appendages, among which the internal spine is sometimes greatly reduced.
In Moldova it is difficult to find a body of water where representatives of the subfamily are not found.

Cyclops vicinus - Cyclops vicinus
Widespread species. In the USSR it is known within all landscape zones, excluding the subtropics. In the east it reaches the river basin. Amur. Found in the tundra, desert, semi-desert, estuaries of the Black and Azov seas. IN recent years found in reservoirs of the Fergana Valley.
In Moldova it is found everywhere, reaching mass development in some reservoirs.
The body of the crustacean is slender. The first three thoracic segments are smooth, the fourth has sharp, drawn-out corners. The genital segment is widened in the upper part, with small projections. The first antennae of the female are 17-segmented, reaching the middle of the second thoracic segment. The legs of the fifth pair are two-segmented. The distal segment is equipped with lateral spines on the inner edge and a long apical seta, at the base of which there are four to five small spines. Furcal branches are long, slightly diverging, with a continuous row of hairs on the inner edges. Of the outermost apical setae of the furca, the inner one is almost twice as long as the outer one (see Table 3).

Table 3. Representatives of copepods and cladocera: 1a – Daphnia magna female; 1b – male; 2 – Moina macrocopa; 3 – Chidorus sphaericus; 4 – Eudiaptomus gracilis; 5 – Cyclops vicinus; 6a – Limnocletodes behningi, female; 6b – male.

The length of the female is 1.2-2.2, the male is 1.1-1.5 mm.
The species is typical for the pelagic zone of lakes, reservoirs, ponds and other small, mainly meso- and eutrophic water bodies. Cyclops avoids dystrophic bodies of water. Occurs in slow flowing rivers Oh. The distribution in the water column is uneven and depends on the physicochemical and biological features reservoir
Cyclops vicinus tolerates increased water mineralization well. Indicated for brackish waters. It occurs at Cl contents of 0.31 – 5.52 g/l. Adapts well to fluctuations in CaO content in water. MgO, chlorides. In relation to the temperature factor, C. vicinus manifests itself as a eurythermic species, which is confirmed by the example of reservoirs in Moldova. Sexually mature cyclops are found in the reservoirs of the republic throughout the year, the maximum number occurs in winter and spring, and winter females are larger than summer ones and are kept in egg sacs more eggs For example, in Komsomolskoe Lake (Chisinau), cyclops was recorded throughout the year, with an average frequency of occurrence of 80%. It reached its highest numerical development (70.5-73.6 thousand specimens/m?) in December and January. The number of eggs per female during this period ranged on average from 50 to 62, which is two and two and a half times more than in the summer population.
In the ponds of the republic, the number of adult individuals of C. vicinus ranges from 2 to 110 thousand specimens/m? and more, and together with the larval stages reaches 250-300 thousand specimens/m?. In small reservoirs its level increases until March-April, amounting to 63-68 thousand specimens/m?, and by summer it steadily decreases to 1.5-10.7 thousand specimens/m?. In Lake Cahul and the Lower Dniester, Cyclops is found constantly, but there are only a few hundred, less often thousands of specimens per cubic meter. In the Kuchurgan estuary-cooler of the Moldavian State District Power Plant and the Dubossary reservoir, in recent years C. vicinus was found sporadically in small numbers.
The lifespan of a crustacean under experimental conditions is a maximum of 83 days. During this time, it forms up to nine to ten pairs of egg sacs. Fecundity varies widely: 30-101 eggs per female.
IN natural conditions The average fecundity of 220 C. vicinus females is 49, with a maximum of 111 eggs. In young females, the formation of another pair of bags occurs every three to four days, and in old females - eight to eleven days. Nauplius at birth reaches a length of 187 microns. At a temperature of 23 -25°C, the transition to the copepodite stage occurs on the fourth or fifth day with a body length of 215 microns. The cyclops becomes sexually mature on the 25th day with a body length of 1.4 mm.
Cyclops vicinus is included in the food spectrum of many fish. In ponds, for example in March, in food bolus of one-year-old carp and crucian carp there were 9.0 and 6.9, respectively, and two-year-old crucian carp up to 29.9 thousand specimens of cyclops
Even in summer, in the presence of other nutritional components, their number in the food bolus of two-year-old carp and crucian carp reached 1.8-2.2 thousand specimens. At this time, C. vicinus was more intensively consumed by the juveniles of these fish (4.7-6.3 thousand specimens/individual).

Acanthocyclops vernalis - Acanthocyclops vernalis
This is the most mass appearance The genus Acanthocyclops is found in Moldova. It is widespread in the Holarctic. Indicated for all of Europe, Asia, North America etc. In the USSR it is noted from the far north to the far south, including mountainous region Caucasus, in the Asian part, in the north of Siberia and the Far East.
It lives in a wide variety of bodies of water: snow and rain puddles, swamps, ponds, the coastal part of slow-flowing rivers and streams, lakes and reservoirs. Part of the fauna of caves.
The species is characterized by significantly elongated posterior angles of the last thoracic segment, angular outlines of the genital segment, slightly divergent furcal branches, 17-18-segmented antennae, and armament of the distal segment of the legs of the fifth pair with a thick spine and short setae. Of the apical setae of the furcal branches, the innermost one is almost the same length as the outermost one.
The egg sacs are elongated, oval, slightly diverging. The color is yellowish or reddish to bright red.
In relation to water temperature, A. vernalis is eurythermic. Registered at temperatures 1-32°C. Lives in reservoirs with a pH of 4.4-8.2. Known in waters with CaO content reaching 100 mg/l with oxidability up to 115 mg/l O2.
This species is mainly freshwater; it is rarely recorded in salt waters. It is polycyclic, in some small reservoirs it has two sexual periods per year, in permanent ones - one of them occurs in winter. In the dormant stage, it can tolerate drying out of the reservoir.
The lifespan of individuals under experimental conditions reaches 76 days. Maximum fertility was found in individuals from the Transnistrian fish farm (146 eggs) with a female body length (without furcal branches) of 1.56 mm. The average fecundity of the species, derived from the count of eggs of 82 females obtained from the reservoirs of the republic in different times year, is 61 eggs.
At a temperature of 26-27°C, the duration of the nauplial period is two to three days, a mass transition to the copepodite stage is observed on the fourth day. Sexual maturity occurs on the 26th day with a body length of 1.14 mm. According to its feeding method, S. vernalis is a typical predator.
In the reservoirs of the republic, the species is widespread. Occurs all year round, but reaches its greatest numbers in the warm period. In ponds at times there are 125.0, in small reservoirs - 230.0, and in the Maramonovsky reservoir on the Kubolta River in July - 506.0 thousand specimens/m?. The mass appearance of males is observed in July.
Included in the food spectrum of fish of different ages.

Mesocyclops crassus - Mesocyclops (Thermocyclops) crassus
The species is thermophilic. Distributed in Europe and Asia, including Japan and the islands of the Malay Archipelago, Africa, Central America, etc. In the USSR, with the exception northern latitudes, occurs widely. Classified as a complex of cosmopolitan species.
Distinctive features are 17-segmented antennae, the structure of the spermatheca (receptaculum seminis), which has the shape of a hammer, and the armament of the distal segment of the fifth pair of legs with a setaceous spine, the length of which is only slightly shorter than the apical seta; noticeably diverging, short furcal branches. The inner of the outermost apical setae is approximately three to three and a half times longer than the outer. The color varies from yellowish to yellowish-brown. The egg sacs are large, each of them contains at least 6, usually 11-14 eggs.
The length of the female is 0.8-1.0, the male is about 0.6 mm.
Cyclops is a common component of standing and weakly flowing water bodies. The greatest number reaches in fresh water in areas with soft hydrocarbonate-calcium water. It also lives in reservoirs with high mineralization, hard and alkaline water reactions. Mass development of the species occurs within the following limits: water pH - 6.5-9.2; oxidability - 5.9-210 mg 02/l; salinity - 0.07-3.1%. Reliably indicated for slightly saline waters of the eastern part of the Gulf of Finland, the northern part of the Caspian and Aral Seas.
In Moldova, it appears in ponds, reservoirs, Lake Cahul, Kuchurgan Estuary, Dniester, Reut, Prut in late April - early May. With a decrease in temperature to 11-12°C. disappears from the composition of zooplankton. In contrast to other species of this genus, M. crassus does not overwinter in the mud, but dies, leaving resting eggs, from which a new generation hatches in the spring. Therefore, the emergence of adults is delayed by about a month compared to other wintering species. Cyclops breeding begins in mid-May at temperatures above 12-13°C and continues without interruption until 10-12°C. Males are the first to disappear, then the number of egg-bearing females quickly decreases. Young individuals, regardless of hydrothermal conditions, are the last to die.
The peak development of sexually mature cyclops usually occurs in July-August (water temperature 17-23°C). At this time, the ratio between males and females is usually 1:1.3 – 1:1.8.
The ability of the crustacean to reproduce by resting eggs and its plasticity in relation to factors environment favored the wide geographical distribution of M. crassus and the penetration of the species from the reservoirs of the tropics and subtropics far to the north.
The intensity of reproduction of M. crassus depends not so much on temperature conditions, how much depends on the nutritional conditions of crustaceans, which lead a predominantly predatory lifestyle. The main food of the Cyclops is protozoa and juvenile cladocerans. The average daily diet of a crustacean when feeding on protozoa reaches 71.4% of body weight.
Under experimental conditions, the lifespan of M. crassus at a temperature of 23-25°C averages 37 days, and the nauplial stage is four to five days. The massive transition to the copepodite stage occurs on the sixth day.
© 1984. Copyright for the article in the book “Bryozoans, mollusks, arthropods” belongs to A.I. Naberezhny, (Institute of Zoology and Physiology, Academy of Sciences of the MSSR).
Use and copying of the article is permitted with the author indicated and a link to the source

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Cyclops are freshwater planktonic crustaceans that live in almost every body of water. They serve as food for many species of fish, larvae, and fry. But they also eat many different microorganisms. Thanks to the feeding activity of the cyclops, the natural water and its quality improves.

Usually all copepods due to external resemblance In everyday life, aquarists call it a cyclops. The body of the crustacean is divided into segments. The compound head bears one eye, two pairs of antennae, oral apparatus plus a pair of legs-jaws.

Cyclops are freshwater planktonic crustaceans that live in almost every body of water. They serve as food for many species of fish, larvae, and fry. But they also eat many different microorganisms. Thanks to the feeding activity of cyclops, natural water is clarified and its quality improves. They can be successfully used as live, dry and frozen food for aquarium fish.

Cyclops live in coastal strip lakes or rivers. They can be up to 5.5 millimeters long. These crustaceans move in water in leaps and bounds with the help of very powerful antennas. He is pushed by these antennas and makes a leap up or forward, in any direction. The speed of cyclops jerks can reach 75 mm/sec. By the way, if you compare the Cyclops with a submarine, then the Cyclops can swim its length 26 times faster than submarine at medium speed.

Cyclops crustacean

Cyclops are divided by sex into females and males. Cyclops larvae are called nauplii. The color of the Cyclops depends on the food it eats. They can be gray, red, or green. Most cyclops are predators. The ability to jump makes it easier for Cyclops to hunt.

Copepoda comprise several families of lower crustaceans and number about 1,800 species. Small planktonic crustaceans, 0.5-2 mm in size, live in both fresh waters and seas. IN sea ​​waters the most common is Calanus. It makes up a significant part of plankton, which serves as food for many fish in the seas and oceans.

Inhabitants of fresh waters are Cyclops and Diaptomus. Usually, due to their external similarity, all copepods are commonly called Cyclops by aquarists.

General characteristics. The body of the crustacean is divided into segments. The complex head bears one eye, two pairs of antennae, mouthparts, plus a pair of legs-jaws. One pair of antennas is much longer than the other. This pair of antennas is highly developed, their main function is movement. They also often serve to hold the female by the male during mating. Chest of 5 segments, pectoral legs with swimming setae. Abdomen of 4 segments, at the end - a fork. At the base of the female's abdomen there are 1 or 2 egg sacs in which eggs develop. Nauplii larvae emerge from the eggs. The hatched nauplii look completely different from adult crustaceans. Copepods feed on organic debris, tiny aquatic organisms: algae, ciliates, etc. They live in reservoirs all year round.

The Cyclops has not two eyes, but one. Hence another name for the copepod - Cyclops, named after the one-eyed giant from ancient Greek mythology. Cyclops are perfectly adapted to different unfavorable conditions life. When a body of water freezes through or dries out, the cyclops is enveloped in a special substance that they themselves secrete, and a kind of cocoon is formed around the crustacean. In such a cocoon, Cyclops can freeze into ice or remain at the bottom of a dry puddle. Experiments were carried out in which cyclops were preserved in dry silt, which had lain without water for three years. This is why Cyclops appears so quickly in spring and rain puddles.

The second reason for the wide distribution of many species of cyclops should be considered the resistance of crustaceans in an active state to the lack of oxygen in water, its acidic reaction and many other factors unfavorable for other freshwater animals. Cyclops strenuus can live for several days not only in complete absence oxygen, but even in the presence of hydrogen sulfide.

Some other species also tolerate unfavorable gas conditions well. Many cyclops thrive in water with an acidic reaction, with a high content of humic substances and extreme poverty of salts, for example, in reservoirs associated with high-moor (sphagnum) bogs.

If you look closely at the Cyclops through a magnifying glass, you will definitely notice that some crustaceans have small pouches at the end of their bodies - one or two - while others do not. The small sacs are egg sacs, and these crustaceans are female cyclops. Crustaceans without pouches are males. From the testicles of the Cyclops comes the Cyclops larva - nauplius, which is also happily eaten by fish, especially juveniles. Reproducing with high speed, Cyclops, like Daphnia, quickly populates a suitable reservoir.

The methods for catching a cyclops in natural reservoirs, as well as its transportation and maintenance at home, are essentially the same as for daphnia. But compared to daphnia, Cyclops is more tenacious and does not die in large numbers either in the aquarium or in the vessels for storing it.

To catch a cyclops, you must have a net made of thin but dense fabric, otherwise very small cyclops, as well as nauplii, will not be caught.

For fish, hunting cyclops is not an easy task: these crustaceans are very mobile, and catching them is not so easy. When feeding the fry with Cyclops nauplii, they should be given as much as the fish can immediately eat, because the nauplii grow much faster and, remaining uneaten, can eventually attack the fry.

Diaptomus

Diaptomus live in the open part of water bodies. The size of the crustacean is up to 5 mm. Just like cyclops, their color depends on the nutritional base of the reservoir. The body is covered quite hard shell in connection with which he is less willingly eaten by fish than the Cyclops. Diaptomus has a pair of short and a pair of very long anterior antennae, thanks to which it makes a short push, after which it soars for a long time in the water column. This property is used to feed fish that are not able to feed on very mobile aquatic organisms.

In Diaptomus, as well as in Cyclops, both sexes take part in reproduction. Diaptomus females, unlike Cyclops females, have only one egg sac. In terms of their biochemical composition, copepods are in the top ten high-protein foods. In aquarium farming, “Cyclops” is most often used to feed grown juveniles and small-sized fish species.

With a body length of 1-5.5 mm, having an unpaired frontal ocellus, which is why they got their name. The antennae of Cyclops are short, and the antennae used for swimming are single-branched. Cyclops have 4 pairs of developed legs. The fifth pair in males is transformed into an organ for holding the female during the sexual process. They do not have a heart. There are no blood vessels. The organs are washed by colorless hemolymph, the movement of which is facilitated by intestinal pulsation. Breathes throughout the entire surface of the body. Nervous system in the form of the head “brain”, the abdominal cord forming a “ladder”, there are no nodes. About 250 species are known, distributed throughout the globe. They usually live at the bottom of freshwater reservoirs, and only a few live in the water column. Cyclops are predators and feed on protozoa, rotifers, and small crustaceans. They themselves serve as food for many fish and fry. They can serve as intermediate hosts for parasitic worms (guinea worm, broad tapeworm and others).

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• Cyclops- article from the Great Soviet Encyclopedia.

An excerpt characterizing the Cyclops (family)

Prince Andrei knew Denisov from Natasha's stories about her first groom. This memory both sweetly and painfully transported him now to those painful sensations about which he lately I haven’t thought about it for a long time, but they were still in his soul. Recently, so many other and such serious impressions as leaving Smolensk, his arrival in Bald Mountains, the recent death of his father - so many sensations were experienced by him that these memories had not come to him for a long time and, when they came, had no effect on him. him with the same strength. And for Denisov, the series of memories that Bolkonsky’s name evoked was a distant, poetic past, when, after dinner and Natasha’s singing, he, without knowing how, proposed to a fifteen-year-old girl. He smiled at the memories of that time and his love for Natasha and immediately moved on to what now passionately and exclusively occupied him. This was the campaign plan he came up with while serving in the outposts during the retreat. He presented this plan to Barclay de Tolly and now intended to present it to Kutuzov. The plan was based on the fact that the French line of operations was too extended and that instead of, or at the same time, acting from the front, blocking the way for the French, it was necessary to act on their messages. He began to explain his plan to Prince Andrei.
“They can’t hold this entire line.” This is impossible, I answer that they are pg"og"vu; give me five hundred people, I will kill them, it’s veg! One system is pag “Tisan.”

What does a person imagine when he hears a word? "Cyclops"? As a rule, there are two options: if he is far from biology and aquarium hobby, then, most likely, he will decide that we're talking about about the mythical one-eyed giant who threw stones at the ships of Odysseus. If the subject in question has an aquarium or carefully read biology at school, then for him the Cyclops, first of all, will look like a tiny crustacean, upon closer examination, much more mysterious and terrible than the mythical giant.

Several times I came across cyclops while studying silt from an aquarium, however, these crustaceans are rare guests in an aquarium. The real dominance of cyclops was discovered in water from stagnant shallow waters. These crustaceans stood out among the other zooplankton swarming in the bowl with their striking bright green (almost fluorescent) color. What they ate to achieve such an effect remains a mystery to us.

Who are the Cyclops?

Well, Firstly, this is a popular fish food, along with gammarus, but this aspect of their life (more precisely, death) is of little interest, so we will not dwell on it.

Secondly, these are small (0.6-6 mm) crustaceans belonging to the order copepods.

Classification of Cyclops

Not everything is clear with the classification of Cyclops. So, according to Wikipedia it looks like this:

• Type: Arthropods
• Subtype: Crustaceans
• Class: Maxillopods
• Subclass: Copepods
• Squad: Cyclops
• Family: Cyclops

That is, here, shaking the foundations of my worldview, crustaceans are not a class, but a subtype. Copepods are classified as a subclass maxillopods. In general, perhaps it is more correct and more modern, but for simple amateurs who do not go into the taxonomic jungle, it is easier to rely on the old classification (TSB), so at least there is a chance to remember:

• Type: Arthropods(Arthropoda)
• Class: Crustaceans(Crustacea)
• Squad: Copepods(Copepoda)
• Family: Cyclops(Cyclopidae)
• Genus: Cyclops
• View: Cyclops coronatus

The structure of the Cyclops

Where did the name come from "Cyclops" It’s not difficult to guess - our hero has only one eye, but he has enough.

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The body of the Cyclops is divided into a cephalothorax and abdomen. In front there are two pairs of branched antennae (of course, not nearly as branched as those). On the underside of the abdomen there are 4 pairs of developed rowing legs. The fifth pair in males is transformed into a special grip for holding the female during mating. The female has paired egg sacs on the sides of her abdomen.

In comparison with, the internal structure of the Cyclops looks simplified. It has neither a heart nor gills. Circulatory system absent: the organs are washed by hemolymph, moving due to the pulsation of the intestines. Absorption of oxygen from water occurs over the entire surface of the body.

Unlike Daphnia, Cyclops reproduce sexually. Most sources say that parthenogenesis is not observed in copepods.

Cyclops habitats

Cyclops are ubiquitous and have proven themselves to be one of the most hardcore survivalists. They live in winter reservoirs under a crust of ice, in acidic and hot springs, in waters with an insignificant oxygen content and lethal amounts of hydrogen sulfide, in general, almost everywhere.

When a body of water freezes through or dries out, the cyclops “preserves” itself by secreting a special substance that forms a kind of cocoon around the crustacean. In such a cocoon, Cyclops can freeze into ice or remain at the bottom of a dry puddle. Experiments were carried out in which cyclops were preserved in dry silt, which had lain without water for three years.

By nature of feeding, Cyclops is a predator. It feeds on rotifers, small crustaceans, in general, everything it can catch.

Cyclops is an extremely fast creature. Its movements are so rapid that it is almost impossible to catch it through the lens of a camera or microscope without first immobilizing it.

Cyclops (Cyclops coronatus), side view

When there comes a short moment of peace and focus on it, it still turns out that the restless crustacean takes off exactly 1/100 of a second before pressing the shutter button. Also, it is not always possible to suck it up with a syringe the first time, which turns the process of catching a Cyclops for study into a real safari.

In the following photos taken through microscope, Cyclops are shown from the side, covered with colonies of ciliates. Although the individuals were still alive, their end was not far off: such a number of sticks stuck to each other usually indicates the imminent end of the carrier.

Cyclops and the Suvoyki

The rowing legs are clearly visible here. Due to the shape of the Cyclops, most images (including textbooks) show the crustacean from the back.

Half-dead female cyclops, covered with suvoys

That's probably all I can say about the Cyclops.
If you have read this article, I recommend that you also read it, because. Cyclops and Daphnia are almost always mentioned side by side as one of the most common inhabitants of our water bodies.