Amphipod crustacean animal belonging to the order of higher crayfish (Amphipoda). In total, about 9,000 species of crustaceans that live at the bottom of the seas and other bodies of water around the world are known. Most crustaceans belonging to this order live in the coastal zone near the surf, can get ashore. And also in this unit parasitic forms are presented to them whale lice belong.
Origin of view and description
Amphipoda (Amphipoda) arthropod animals belonging to the class of higher crayfish order amphipods. For the first time, this detachment was described by the French entomologist Pierre Andre Latrey in 1817. This squad includes more than 9000 species of crustaceans. Amphipods are very ancient creatures, it is known that these crustaceans inhabited the benthos of the seas and fresh water bodies at the beginning of the Stone Age of the Paleozoic era, about 350 million years ago.
However, due to the lack of carapace, the remains of these animals were almost not preserved, only 12 specimens of ancient crustaceans of this detachment are known. Fossils of ancient amphipods that lived during the Eocene were preserved. These fossils have survived to this day thanks to amber. An ancient animal fell into a drop of amber and could not get out of it, and only thanks to this circumstance can we know that these creatures lived during the Paleozoic era.
In 2013, an amphibian was described that lived in the Triassic period of the Mesozoic era, which is almost 200 million years older than the previous specimen.
This amphipod species Rosagammarus minichiellus in the same year, this fossil was described by a group of scientists under the representation of Mark McMenamine. At the moment, the population of crustaceans is extremely diverse. And also some planktonic organisms are included in this order.
Appearance and description
Photo: What does the amphipod look like?
Amphipods are very small crustaceans. The size of the average individual in length is only about 10 mm, however, large individuals of about 25 mm in size are also found, but rarely. Representatives of small species of amphipods are very tiny and their size is only 1 mm in length.
The body of the amphipods is flattened on the sides. The main difference between amphipods and other crustaceans is the absence of carp. On the chest, the anterior segment is completely merged with the head. The limbs on the first segment are represented by the jaw. The limbs on the chest have a different structure. On the front pair of limbs there are large false claws. These claws are required to capture food. The next two pairs end with claws. Only on the front claws are directed forward, and the rear claws are directed back.
Thanks to these claws, the animal can easily move along the subrostat. Between the 2 and 7 thoracic segments are located the gills. The belly of the amphipod is divided into several sections - the urosoma and pleosome. Each of the sections includes 3 segments. On the segments of the pleosome are pleopods, bifurcated limbs serving for swimming.
On the urethra, uropods are located, thanks to which the crustacean can jump high and move fairly quickly along the shore and along the bottom of the reservoir. The creepers are pretty strong. The excretory system is represented by the intestine and anus.
Where does the amphibian live?
Photo: Side-float in the river
Amphipods are extremely common creatures. They live in almost all freshwater reservoirs, seas, at the bottom of the oceans. In addition, many amphipods live in groundwater. They can be found in the keys and wells of the Caucasus, Ukraine in western Europe.
Sub-order Ingol-fiellidea lives in the underground waters of Africa, southern Europe and America. And also several species of these crustaceans live in the capillary passages of sand on the shores of Peru, Lamanche and the Gulf of Thailand. Species of Gammarus pulex, G. kischineffensis, G. balcanicus. They inhabit the reservoirs of England, Moldova, Germany and Romania. In our country, these crustaceans live in almost all reservoirs.
Marine amphipods live in the Azov, Black and Caspian Sea. Amphibians of several species live in the Volga, Oka and Kama rivers: Niphargoides sarsi, Dikerogammarus haemobaphes, Niphargoides sarsi. In the Yenisei and Angarsk reservoir there are more than 20 species of these crustaceans. Well, the most diverse fauna in Lake Baikal. At the bottom of Lake Baikal, 240 species of crustaceans live. All crustaceans live at the bottom of reservoirs and lead a planktonic lifestyle.
An interesting fact: At the bottom of the Oka River, only in its lower reaches, there are about 170 thousand specimens of amphipods of the genus Corophium per square meter of bottom.
Now you know where the amphibian is found. Let's find out what he eats.
What do amphipods eat?
Photo: crustacean amphipod
Almost all amphibians are omnivores.
The main diet of amphipods includes:
- underwater plants (both living parts and dead ones);
- the remains of fish and other animals;
- small animals.
The way you eat can be different. These crustaceans bite large food with chews and break it into small pieces. Powerful jaws hold pieces of food without letting it fall out of the mouth. Some types of amphipods feed by filtering the suspension that the waves bring. These crustaceans usually live in the coastal strip. When they feel that the wave is moving away from the coast, the crayfish hide in the ground only leaning a little out of it, when the ground exposes the crustaceans are immersed in it whole, the species Niphargoides maeoticus usually feeds on it.
Crustacean species Corophiidae, Leptocheirus and Ampeliscidae feed without leaving their houses. There, these animals begin to muddy the topsoil with their rear antennas. Algae and bacteria enter the water, and the cancer filters the water by passing it through a network of bristles, which is located on the front legs. Predators among amphipods are sea goats.
These small crustaceans attack smaller relatives, worms, and jellyfish. Planktonic amphipods of the species Lysianassidae live on jellyfish and lead a semi-parasitic lifestyle. Parasitic species of amphipods Cyamidae whale lice. These small parasites settle on whales near the anus and feed on the skin of whales, gnawing deep ulcers.
Features of character and lifestyle
Most amphipods lead a semi-underwater lifestyle. During the day, they live at the bottom of the reservoir, at night, these small crustaceans get out on land and can crawl along the beach in search of food. Usually they eat rotting algae that they throw ashore in waves. In the daytime, crustaceans return to the reservoir or hide in the soil, protecting the gills from drying out.
Like many crayfish, amphipods breathe with gills; gill plates are penetrated by thin vessels that retain moisture and this allows crustaceans to get out to land. Crustaceans have an amazing ability to navigate in space; even when moving far away from the water, they can accurately determine where they need to return.
Some amphipods are looking for snags and branches, eating sawdust and dust. Predatory amphipods, sea goats, almost all the time hide among thickets of grass. They hunt down prey for a long time sitting in one place, slightly raising their front claws, as soon as she sees the prey sharply and attacks it.
Whale lice lead a parasitic lifestyle, and spend almost their entire life on whales eating their skin. Small crustaceans living on the seabed lead a quiet lifestyle. Some practically do not leave their minks, eating by filtering constantly digging the bottom.
Social structure and reproduction
Photo: Cancer Amphipod
Amphipods are heterosexual creatures. Often sexual dimorphism is very pronounced. Depending on the species, males can be larger than females, or vice versa. In the Gammaridae family, males are several times larger than females. The Leptocheirus family, on the contrary, has more males than females. Sexually mature females of all types of amphipods have a brood bag.
An interesting fact: The development of male sexual characteristics in amphipods is due to the presence of a special hormone that is secreted by the endogenous androgenic glands. Transplantation of these glands of a female individual led to the degeneration of the female ovaries into the testes.
In Gammarus duebeni, the sex of the offspring is determined by the temperature at which the eggs mature. In the cold season, males are hatched; in the warm season, females are born. The mating process in amphipods lasts several days. The male is pressed against the back of the female, holding its strong claws on the front and rear edges of the fifth thoracic segment of the female in anticipation of molting.
After molting, the male moves to the abdomen of the female and folds the abdominal legs together, slipping them several times between the back plates of the brood bag. At this time, semen is secreted from the genital openings. With the help of the abdominal legs, sperm is transferred into the brood bag. After 4 hours, eggs are laid by the female in this bag and then they are fertilized. In different types of amphipods, the number of eggs that the female lays is different. Basically, females lay 5 to 100 eggs per mating.
But some species are more fertile, for example, Gammara-canthus loricatus lay up to 336 eggs, Amathillina spinosa up to 240. The White Sea amphipods are most prolific, Apuguh nugax, after one pairing, the female carries up to a thousand embryos. It takes 14 to 30 days before the small crustaceans leave the mother’s brood bag.
Small crustaceans grow very quickly, surviving about 13 molts. Most species of amphipods breed in the warm season, however, amphipods of the genus Anisogammarus carry eggs all winter, and by spring, small crustaceans are born. The average life expectancy of amphipods is about 2 years. Representatives of the species Niphargus orcinus virei live most of all. They can live up to 30 years, but on average they live about 6 years.
Natural enemies of amphipods
Photo: What does the amphipod look like?
The main enemies of amphipods are:
- whales and killer whales;
- frogs and other amphibians;
- insects and their larvae;
- birds (mostly sandpipers sandpit).
Amphipods are very small and almost defenseless creatures. Therefore, in the natural environment of the enemies of these crustaceans abound. Because of this, crustaceans try to lead a more or less secretive lifestyle. In rivers, eel, burbot, perch, roach, bream and many other fish prey on amphipods. Eels are considered the most dangerous enemies of these crustaceans as these fish constantly dig the soil and easily climb into the crayfish burrows.
On the shore of crayfish, birds and mammalian predators lie in wait. But most amphipods die not from the fact that they fall into the clutches of predators, but from diseases. And the most dangerous of them is the plague of the dog. It is the plague that destroys thousands of crustaceans annually. Crustaceans and parasitic diseases suffer, even parasites settle on these small creatures. The most vulnerable crustaceans received any injuries, various bacteria quickly multiply on the wounds.
Also adverse factors include water pollution. Amphipods are very sensitive to the ingress of harmful substances into the water; cases of mass death of these crustaceans in places of severe pollution of water bodies are known.
Population and species status
Amphipods are the most numerous class of crustaceans. This class does not need special protection. It is impossible to track the number of populations because of the very large number of crustaceans of various species that live in all water bodies. These small crustaceans feel comfortable in the wild, adapt well to various environmental conditions and multiply rapidly.
Amphipod fishing is permitted. Small crustaceans in our country are caught in an environmentally friendly way. Krill meat is a tasty and nutritious food rich in vitamins and minerals. Many types of amphipods are used in fishing as bait. Fishermen use mormyshka for fishing perches, breams, crucian carp and other types of fish.
Amphipods are real orderlies of ponds. These small crustaceans eat the remains of animal corpses, decaying plants, plankton. That is, all in which dangerous and pathogenic bacteria can multiply successfully. Feeding these crustaceans purify water, making it clean and transparent. Predatory crustacean species regulate the population of jellyfish and other creatures on which they hunt.
All that can be done for amphipods is to monitor the cleanliness of water bodies, install treatment facilities at enterprises and make sure that dangerous and toxic substances do not get into the water.
An interesting fact: amphipods are also called sea fleas, but unlike terrestrial fleas, these creatures do not harm humans and terrestrial mammals.
Amphipod an amazing creature that inhabits large numbers of water bodies around the world. Thousands of these small crustaceans live in any reservoir. Despite their small size, they are very nimble creatures leading an active lifestyle. They know how to swim well, and rather quickly move along sandy beaches with the help of jumps. Sometimes these little creatures are compared to vultures because of their habit of eating carrion. Crustaceans have a very important role in the ecosystem, as they are the orderlies of water bodies and are food for a large number of underwater animals, mammals and birds.