The smallest crustacean daphnia received in the peoplethe second name of the flea is watery for its external resemblance to the insect parasite and the ability to move by jumping. But, besides this, they have nothing in common, since they are representatives of absolutely different classes.
Daphnia is the most famous and numerousrepresentative of the family Daphniidae. The skin of this organism is bivalve, with two hooks on the end of the body and one spherical, mobile eye, which sets in motion three pairs of oculomotor muscles. The body of the daphnia is transparent and allows you to see everything that happens in her body. Even the slightest contraction of the muscles of the crustacean can, if desired, be examined in a microscope.
Despite its tiny size, it's prettyAn amazing organism is a water flea. The description of the species marks many interesting features in its internal structure. The kidneys of daphnia are near the mouth, the brain - near the esophagus, and the heart - on the back of the trunk. The blood is yellowish, contains white corpuscles - phagocytes, which, if necessary, protect the organism of the crustacean from bacteria, fungi and alien microorganisms.
The water flea has five pairs of legs, but they servenot so much for movement, as for directing the flow of water to the mouth, which it filters for the presence of nutrients. Breathing is carried out directly through the covers of the body.
Daphnia are widespread almostthe whole globe. Most of them are in the subtropics and in latitudes with a temperate climate. Basically, the water flea lives in stagnant water bodies (lakes, ponds, rivers with slow currents), and also in puddles. Rapidly multiplies, extremely tenacious, so its abundance is quite large. Usually located in the water column, moves irregularly or crawls on the bottom (due to the chest legs).
In summer daphnia swim quickly, but when they comeunfavorable times - freeze. Even if the puddle in which they were, dries up, they come back to life right after it is filled again.
Most daphnia are herbivores, butthere are also predators. The water flea processes phytoplankton, fungi, bacteria, as well as rotting remnants of animal tissue after its use by large predators.
The family of daphnia is quite numerous.Only in Europe and North America there are about 150 species of these crustaceans. In Russia, some of them are especially common: magna, puleks, kukulat, galleate, cristata. They all live in a variety of water bodies.
The largest water flea is daphnia magna.The female has a length of up to 6 mm, the male is three times smaller. The period of maturation of newborn daphnia lasts two weeks. The female also lays eggs every two weeks (about three dozen eggs). First, newborns have microscopic dimensions. But then they are actively growing. Lives this species for about three months.
Another common form is Daphnia Puleks.Representatives of its slightly smaller size - females about four millimeters, males are half as large. They are very prolific - a laying of fifteen eggs occurs once every five. These water fleas live relatively long - the life cycle can be up to a month and a half. It varies depending on the conditions of existence. For example, a rise in temperature shortens life due to the fact that the metabolism of crustaceans increases.
Water fleas are unusually prolific.In all Daphnia egg laying is divided into winter and summer. Eggs have their own characteristics in a certain period. So, for example, in winter laying, they are covered with a denser shell and the number of them is small (about 2 pieces), and in summer they are much larger. All these features are due not to the change of seasons and conditions of existence, but to the presence of males. In summer, when the population of males is very small, eggs of daphnia appear and are carried without fertilization. Eggs fertilized by males are postponed only once a year - in the fall. For its life cycle, the female is capable of giving offspring up to 25 times.
Despite the fact that daphnia is called a fleawater, it has no relation to bites. Nevertheless, a person can cause harm. Everything is in a high degree of allergenicity. This is attributed to the fact that during the period of violent flowering of plants, the pollen enters the water, in which there are daphnia, and those, in turn, filtering it, can capture those same particles of pollen. Then, when the crustaceans are dried, this pollen remains and can cause a strong allergic reaction in the human body, which is often mistaken for the bite of a water flea.
Symptoms of allergies are often typical - inflammation of the conjunctiva of the eye (conjunctivitis), lacrimation, frequent sneezing, nasal congestion and difficulty breathing.
Sometimes there may be rashes on the body, accompanied by severe itching.
In turn, daphnia serve as a universal food for aquarium fish. To this end, they are bred at home.
It is only necessary to catch daphnia in a standing pond andto provide them with living conditions close to nature. Catching crustaceans is in pools where there is little or no fish, since in the absence of predators, daphnia will be more and less likely to be affected by any infection.
Water fleas in the aquarium should be contained inthe water in which they live, because in tap water there is no food, which they eat. Also, you need to carefully consider the choice of packaging, in which the crustaceans will be contained. After all, such materials as, for example, polypropylene, when exposed to water, can release harmful substances, and daphnia will simply perish.
Contained in aquarium conditions daphnia needa lot of light. In a well-lit room, they feel great and give good offspring. In addition, daphnia can not tolerate narrowness. Since they multiply rapidly, you need to constantly monitor that they have enough space and periodically move part of the water fleas to another aquarium. This can be explained by the fact that the crustaceans are very sensitive to lack of oxygen and quickly die, not receiving it.
Many aquarists involved in breedingdaphnia, note that the best food for them is baker's yeast. Only to feed the daphnids should be carefully - if you pour too much food, the water will become cloudy, and oxygen will not be enough for the crustaceans. On the aquarium in five liters you need the amount of yeast, equal to the size of the match head. It is necessary to stir them in a teaspoon of water and gradually pour into the aquarium. Also, food for the crustaceans are green algae, including Euglena Green and Chlorella.
It is also important to note that a certain temperature is necessary for them. This, according to experts, from 22 to 25 degrees. It is in such conditions that water fleas reproduce in the basin of a natural body of water.
One should not allow water to boil and change the water (the third part of the entire volume) at least once or twice a week.
Daphnia crabs perfectly filter water from bacteria. Therefore, many aquarists plant them for water purification - it does not bloom and remains clean for a long time.
At first glance, it may seem thatDaphnia breeding at home is a very laborious, time-consuming process. Nevertheless, these crustaceans are a year-round ecological net food for most fish species (both fry and adult individuals).
Water flea is very sensitive to dirt.habitat and changes in its ionic composition (sodium, magnesium, calcium, and so on). For this reason, crustaceans are often used to determine the quality of water (both tap water and water from open water bodies).
