First, let's talk a little about these interesting creatures.
Alluring crabs (family Ocipodidae, Uca sp.) Got their name for a reason, as they have a very original structure of claws and very original behavior.
In male crabs, one of the claws is much larger than the other. This large claw, and in case of danger, will help scare off the enemy, and will lure and attract a crab friend. So the crabs sit near their burrows and swing their claws like a traffic controller at an intersection.
And yet, some species of alluring crabs are capable of making sounds a bit like chirping cicadas or grasshoppers. What interesting creatures they are!
Undoubtedly, they are curious to watch and some lovers of exotic aquarium keep these crabs in their aquariums.
However, for a full and prosperous life, they need to create optimal living conditions in the aquarium. This is not as easy as it seems at first glance.
However, it is not so difficult, especially after you read the instructions of Sergei Leonov (Mikhailovka, Volgograd region, Russia) on arranging a dwelling for alluring crabs, which he kindly shared with the Tashkent aquarium site.
How to arrange a home for an alluring crab
For the arrangement of the crab maker, several necessary conditions must be met.
This primarily concerns the substrate. It should be light and free-flowing, so we recommend using coral sand for this purpose.
Why coral? Not because I like to show off (which is, that is!), But because everything is conditioned by the practical side.
So, what prompted me besides the fact that a 14-kilogram bag was gathering dust in my storehouse ( photo 1) and the fact that he is awesome-handsome?
It's all about such a trivial thing as the importance of maintaining a strictly set pH value for anyone wearing a shield (read carapace!) On their back. It (the bag), or rather its contents, does not allow this pH to drop and will keep it at an acceptable level of about 7.
It is very difficult to maintain this very "PyHy" at the proper level in such a small container as mine.
The aquarium is only twenty liters, because only two crabs live, and I was not even going to keep the colony.
For crabs, bottom area is the most important. Therefore, we took a square jar with a small height ( photo 2).
The size of this aquarium is just perfect also from the side that it is like a glove, that in height, in width, it fits under the shelves of my aquarium cabinets ( photo 3).
So, the coral soil has a slightly grayish color. Therefore, before placing it in the aquarium, rinse it out a little.
We take a small bowl - it is best to have a separate nylon container for aquarium affairs - and very carefully rinse the soil under running water with a small pressure of warm water.
If the sand is fine, like mine is 0.5-1 mm, then you need to be doubly careful. It gets agitated very easily, and in this way, through an oversight, I have almost half of the initial mass left.
The sand will foam and paint the water white, but do not be afraid, this is normal ( photo 4). It should be so!
If this is not the case, then he is either already washed, or ... you need to already start to get scared. Fill, rinse, drain three or four times until the sand becomes boiling white ( photo 5).
After the soil is washed and squeezed out (a little), evenly, in a small layer, cover the bottom surface with this coral sand with a gradual rise to the wall or corner, like mine ( photo 6).
In addition to the layer under water and protruding parts of the land, it is very pleasant for crabs to wander in shallow water. There is nothing complicated about it. We just make a small embankment.
In the middle of the bottom of the aquarium we put a structure along which crabs can get out to the surface ( photo 7).
Why in the middle? Yes, simply because they, as "wounded in one place", are constantly ready to escape and will not fail to use the edge of the aquarium if they reach it. If the decoration is in the middle, then there will be only water around.
Water for the alluring crab
photo 9).Thus, we have created all the necessary conditions for keeping alluring crabs, which, I am sure, will delight you with their originality and cheerful disposition.
Belongs to the class crustaceans. The alluring crab is a small, highly organized semi-terrestrial crustacean. A feature of this animal is a giant right claw. During the movement, the alluring crab makes certain movements with a large pincer, as if luring individuals of the opposite sex to itself and vice versa, scaring away other crustaceans from itself. Therefore, the crab received such a name. Also, the alluring crab has regenerative abilities. The claw that has fallen off, for whatever reason, grows back again. In some cases, the new claw of the alluring crab grows larger than the previous claw.
The structure of the body of the alluring crab
The body of the alluring crab, like that of other representatives of this species of crustaceans, consists of a cephalothorax and a reduced abdomen. The whole body is made up of segments. The segmented head, consisting of two pairs of small antennae and stalked eyes, is smoothly connected by the segmented abdominal region. The head consists of three pairs of jaws and three pairs of legs. The chest consists of five pairs of walking legs, of which the first pair of legs is pincer-shaped. The head and chest of the alluring crab is covered with carapace. Carapax is a shell that covers the body of a beckoning crab. Only males have a huge claw. In females, both the right and left pincers have the same structure.
Characteristics of the animal:
Dimensions: body length without limbs 1.5-2.5 cm, with claws 5-10 cm.
Color: the body of the alluring crab has different colors, mainly dark gray, dark red and black. Large claw and limbs: red-yellow-white and other smooth transition colors.
Feeding the beckoning crab
The digestive system of the alluring crab consists of three parts: the middle - endodermal section, the anterior section and the posterior rectum. The anterior section consists of the esophagus and stomach. The alluring crab feeds mainly on small crustaceans, algae, aquatic plants and detritus, and can also consume large quantities of soil.
Reproduction and habitation of the alluring crab
Alluring crabs are dioecious animals. The female genital openings are located on the sixth thoracic segment, located near the third pair of walking legs. The male genital openings are located on the eighth thoracic segment, located at the fifth pair of walking legs. In males, the holes are tubes, which during the breeding season are filled with sex cells. When mating, the male introduces these cells into the genital openings of the female. The female of the alluring crab fixes the eggs on the abdominal legs and maintains them there until hatching.
Alluring crabs are widespread in tropical waters, mainly the islands of the Pacific and Indian oceans.
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The alluring crab (Latin Uca tangeri) was first described in 1835 by the French naturalist Joseph Fortuné Théodore Eydoux. The ship with him on board ran aground near the Algerian city of Tangier, and the naturalist had no choice but to study the underwater inhabitants. In memory of this significant event, the crab got its Latin name.
Behavior
This decapod crustacean belongs to the Ocypodidae family of the Pleocyemata suborder and lives on the east coast of the Atlantic Ocean. Due to the fact that its combat claw can sometimes reach very impressive dimensions and weigh more than half the weight of the crab itself, among many African peoples it is considered a product of evil forces and even a great sorcerer who can catch spoilage on an inexperienced diver or fisherman.
The habitat extends to the southern coast of Portugal and Spain, as well as the coastal waters of Africa from Morocco to Angola.
Large colonies of these crabs are found mainly in mangroves, where they find refuge in bizarre labyrinths of roots. They love salt water, but often also settle at river estuaries, carefully avoiding sandy, rocky and pebbly coastlines.
An important feature for choosing their place of residence is the regular hot flashes. Whole crowds of alluring crabs hunt in the accumulations of various garbage thrown ashore by the ocean. They often settle directly in the vicinity of coastal cities, hoping to profit well from the products of human life.
In the colonies of Uca tangeri, each individual pulls out his own burrow and carefully guards it from congeners. The circular entrance opening continues in a narrow cylindrical corridor that widens at the end to form a small, cozy living chamber.
Food
The alluring crab usually goes fishing at night, but it can show some activity during the day, if the weather is not hot and dry. With the onset of low tide, he leaves the shelter and quickly moves sideways along the shallows in search of food supplies.
Its diet consists of rotting algae, small marine life and carrion.
A voracious creature, in order to get to nutrients, it filters out a huge amount of silt and sand. Having sent another portion into his mouth, he mixes it with saliva and gently grinds it with his jaws, swallowing all the most edible, and removes the remainder from the intestines in the form of small lumps.
By the end of low tide, a whole heap of such lumps grows near his burrow. Before the end of low tide, a hardworking and thrifty crab pulls into its burrow rather large pieces of falling, so that there is something to eat during the high tide.
Love of fighting
Alluring crabs have an extremely quarrelsome character. They often fight among themselves, and not only males, but also females. Gentlemen, seeing the enemy, strive to sneak up on him from the side and bite him heartily with a powerful pincer, while the ladies prefer to push each other with their shells.
The fighting can last for several minutes and often end in serious injury. A male who has lost its claw may remain a bachelor during the period of mass marriages. He just physically will have nothing to lure his girlfriends to procreate. However, after the next molt, the claw will appear again, sometimes larger and more beautiful than the previous one.
Reproduction
During the mating season, the male carapace acquires a brighter color and even shines as if polished. The male changes his usual gait to make a proper impression on the female.
His movements become more proud and imposing, accompanied by frequent leaps to the side and persistent strokes of a large pincer. If the dance talents of the gentleman make a favorable impression on the female, she comes closer to him.
The charming dancer quickly pushes her into his burrow, until she has time to be disappointed in his charms. An hour later, she leaves the hospitable burrow and lays eggs over time, which she carries on her abdominal limbs in special capsules. When the development of the embryos approaches the end, she enters the water and leaves eggs, returning back to the colony.
One female can lay several thousand eggs.
From the laid eggs, larvae, about 1 mm long, freely floating in the plankton, called zoea, appear. After multiple molts, they turn into adult crabs and go to look for a place for themselves in the nearest colony.
Crabs moult regularly, shedding old and cramped shells. After each molt, the claws grow in size, continuing to grow until puberty.
Description
The large claw grows up to 60-65 mm, while the length of the shell is 33 mm, and the width is 47 mm. The surfaces of the claws have a pronounced grainy texture. Their upper half is mobile and, joining the lower one, acts as forceps.
One of the pincers is huge and serves as a military weapon and for plucking off large pieces of food.
The head and chest are covered with a quadrangular carapace with a bumpy surface. There are four pairs of walking legs.
On the sides of the base of the rostrum, there are slit-like orbits, in which faceted eyes set at the ends of the stalks are located.
The life span of the alluring crab is about 3-4 years. Few survive to such an old age, because they have a lot of natural enemies. At low tide, they are eaten by tens of thousands of various birds and animals.
- Class: Crustacea = Crustaceans, crayfish
- Subclass: Malacostraca = Higher Crayfish
- Order: Decapoda = Decapod crustaceans (crayfish, crabs ...)
- Suborder: Pleocyemata Burkenroad, 1963 = Crabs, short-tailed crayfish
- Infraorder: Brachyura Latreille, 1802 = Crabs, short-tailed crayfish
- Family: Ocipodidae = Ocipodids
- Species: Uca pugilator = Fiddler crab
- Species: Uca tetragonon = Alluring Crab
- Species: Uca perplexa = Alluring Crab
Genus: Uca = Alluring crabs
The name “alluring” crab was given due to its special habit of making alluring movements of its large pincers, with which it simultaneously scares away other males and lures the female. At night, or being in dense thickets, in conditions of poor visibility, the male has not to wave his claw, but to knock on the ground. Such rather loud sounds and vibrations also attract the female, and she hurries to the call of the male.
It is worth noting that alluring crabs lead an almost land-based lifestyle. These crabs dig their burrows on the seashore in the region of high tide, during which they hide in burrows, and at low tide they are looking for food. There are two species of beckoning crabs, one of which (Uca tetragonon) lives in the lower part of the coast, which is flooded at high tide. He digs minks among the fragments of shells and fragments of dead coral.
And the second species (Uca perplexa) inhabits the upper bank and lives only on muddy soils. At times, representatives of both species go far enough from the coast and find themselves in moist forest zones with fresh water bodies.
Female Californian violin crab (Fiddler crab) often inspect and check more than 100 males, even inspecting the males' bachelor housing before choosing a mating mate. During the process of seducing the female, the male violin crab stands at the entrance to his hole on the shore and, waving his claw, gives the female a “come here” sign, enticing her. Interested females inspect the males and, if they like what they see, partially or completely enter the male's den to measure it. When the male is selected, the female enters his house, plugging the entrance to the hole. Having settled down, the couple begins to mate and lay eggs, which will later be washed out of the burrow by waves.
Scientists have long been intrigued by the tiny violin crabs' ability to change the color of their shells from bright blue to dull, muddy hues. Until now, the reason for this color change was unknown. But recently, researchers from the Australian National University (ANU) found that crabs change color so that they are not eaten by birds of prey. To do this, scientists studied a specific species of the Uca vomeris violin crab on the northeast coast of Australia. Since some populations of these crabs are distinguished by dull colors, and in other places they are very colorful, the researchers examined the color changes of the crabs in three different areas: one group was dull, the other bright, and the third was mixed. It turned out that there were very few birds of prey in the habitat of bright blue crabs compared to the dominance of predators in the habitats of dull crustaceans.
To confirm their hunch, the scientists created an experimental model and tested whether crabs change their shell color when threatened to be eaten. They found two very colorful crabs living close to each other and placed a wooden screen between them. One crab was left alone, and the other every few minutes felt the close attention of a bird of prey. In reality, the bird was not real - its role was played by a black ball suspended from a fishing line. But the crabs have poor eyesight, and the ball was enough for the crustacean to feel the presence of the bird.
During several days spent "under the supervision of a bird", the crab changed color to a dirty shade, while the other remained bright. Scientists suspect that the blue color is usually used by crabs to identify neighbors-congeners in order to avoid unnecessary quarrels with them. The researchers' next step is to find out if the lackluster coloration is affecting the "companionship" between crabs.
By the way, earlier violin crabs surprised scientists with their social skills. In addition, they have been recognized as the most choosy and picky creatures on Earth.
The alluring crab gets its name from its characteristic complex alluring movements that scare off competitors and at the same time attract the female. The male of the alluring crab has a large, brightly colored claw.
& nbsp & nbsp Class - Crustaceans& nbsp & nbsp Subclass - Higher crustaceans
& nbsp & nbsp Row - Decapods
& nbsp & nbsp Genus - Uca
& nbsp & nbsp Basic data:
SIZE
Length: 3-4 cm.
Claw length: up to 5 cm.
REPRODUCTION
Puberty: from 1-2 years old.
Marriage period: several times a year (depending on the species, place of residence and ebb and flow).
Number of eggs: several hundred.
Incubation: 7-10 days; microscopic larvae hatch from the eggs, which float in the plankton.
LIFESTYLE
Habits: single inhabitant of the littoral zone; lives in burrows.
Food: organic particles.
RELATED SPECIES
Many species of crabs belong to the genus. They vary in color and size.
& nbsp & nbsp Many species belong to the genus of alluring crabs. These small, sedentary inhabitants of warm and muddy coastal waters are common throughout the world. The ebb and flow of the tide determines the way of feeding the alluring crabs, since these crustaceans cannot feed under water.
FOOD
& nbsp & nbsp While searching for food, alluring crabs with their claws, front gripping legs dig up sand and silt, grab food with their jaws and present it to the mouth opening. In the mouth, the edible part is sifted out of the food, and inedible residues are excreted. Because sand and silt are low in nutrients, tempting crabs must spend a lot of time looking for food. Especially males spend a lot of time on food. This is because they can only use the left claw. The right claw is too large to hold food comfortably and interferes with males during feeding.REPRODUCTION
& nbsp & nbsp With the beginning of the mating season, males begin to care for the female. With their right claw, they make special, very interesting movements. Different types of beckoning crabs carry out the movements of their large claws in different ways. First, the male runs back and forth on the sand, and waves his right claw in front of the female, and then goes forward, hoping that the female will follow him. The researchers noticed that the males, during the mating dance, knock their claws on the ground and stamp their feet, as the locust does. Mating of crabs takes place in the male's burrow. After mating, the female lays a large number of eggs. The larvae of alluring crabs, hatching from their eggs, travel by sea for a long time as part of plankton, they are carried by the waters of the ebb and flow. As they grow, the larvae become more and more like adults. & nbsp & nbsp Once development is complete, they go ashore to spend the rest of their lives in the inflow and outflow area. In the lower part of the littoral, crabs make burrows.
LIFESTYLE
& nbsp & nbsp Adult alluring crabs spend most of their life in the lower part of the littoral zone. They are found both on muddy and sandy soils, in which they tirelessly seek food. On coastal shoals, they very often form dense settlements, but only one crab lives in each burrow. Alluring crabs are sedentary animals, they try not to move away from their holes and in case of the slightest danger they immediately hide in them. & nbsp & nbsp Interestingly, before hiding in the hole, the alluring crab hits the pound with its claws - probably this is how it warns its relatives about the danger. Crabs breathe with gills.
ENEMIES
& nbsp & nbsp The larvae of crabs, which are transported from place to place in the composition of plankton by the waters of the ebb and flow, become easy prey for a number of predators. Waterfowl eat them in thousands, collecting them from the surface of the water. The alluring crabs that have grown up also have many enemies. They are hunted by martins and frigates. On the coast, crabs are collected by sivk-like birds; their shells are easily smashed by the eider. In addition, crabs become prey for some mammals, for example, noses or striped raccoons. These animals effortlessly dig crabs out of their burrows.& nbsp & nbsp DID YOU KNOW THAT ...
- The world's largest crab is a giant Japanese crab weighing up to 20 kilograms. The span of its claws can reach 3.7 meters. The diameter of the shell of the giant Japanese crab is 30-35 cm.
- As it grows, the alluring crab repeatedly changes its shell. At the same time, he discards the top cover. It takes some time before the new crab shell hardens. While the shell is soft, the crab is very vulnerable.
- Animals like modern crabs existed on Earth 650 million years ago.
- In males of some alluring crabs, the left claw is enlarged, while in these crabs, on the contrary, the right claw is larger than the left.
CLAWS OF BEKING CRABS
& nbsp & nbsp Male alluring crab: differs from the female on the right by a very large, brightly colored pincer. The male's left claw is of normal size. During the mating season, males make complex beckoning movements with a large pincer, frightening off competitors and at the same time attracting a female to themselves.& nbsp & nbsp The female crab has both claws of normal size; with their help it is easy to collect food.
ACCOMMODATION
They are found in warm regions around the world, live in the south of the Atlantic Ocean, in the inflow and outflow zone of the Pacific Ocean and in the Mediterranean Sea.
PRESERVATION
Alluring crabs are quite numerous in all places of their residence. The main danger for them is the crab pickers and the pollution of coastal waters.
