Spawn (biology)

When spawning, the eggs of animals are referred to, in which the eggs are laid in the water. These include fish and amphibians, but also water snails.

Pisces

In fishes, the female ( " Rogner ") sets the spawn - the while he is still within the ovary, also known as roe - to water plants or on the seabed off. Immediately after stopping the eggs from the male ( " milter " ) are inseminated. Unlike Haftlaichern give free spawners their eggs into the open waters. Here, for example, show a so-called doctor fish " depth jump ": After a certain behavior pattern by which synchronize males and females in their swimming behavior, they rise rapidly to several meters upwards. This causes including expanding the swim bladder and thus a higher internal pressure in the fish. As easier and faster ejecting eggs and sperm becomes possible.

Some fish lay redds on the ground, which can be up to two meters wide for large species such as the Danube salmon or salmon. In the males of some species of carp forms during the spawning season a Hautverhornung, referred to as " spawning rash ".

Amphibians

The eggs of amphibians are covered usually by a swelling in water gelatinous layer and stored in different forms of most species in a water body. From the spawn hatch gill -bearing larvae, which develop in waters up to metamorphosis on. In the anurans these are also called tadpoles.

True Frogs ( Ranidae ) set from larger, lumpy spawn clumps. During the spawning of the common frog (Rana temporaria ) often rise to the surface and form large " pancake ", the spawning of other species remains mostly submerged. In addition, frogs often form large spawning societies from which some quite large " spawning clusters " result. Tree frogs ( Hylidae ) fix their small, about the size of plums spawn clumps happy to water plants. This also make the water frogs ( Pelophylax spec.), Their spawning bales are sometimes very different in size. In Europe, the genuine frogs have in common that the eggs of early -spawning species in comparatively dark, which are the late -spawning species relatively bright.

True Toads ( Bufonidae ) stretch long spawning cords between aquatic plants and submerged branches. Here, each of the two ovaries produces a string with the spawning depending on the type of one or two rows of eggs that can be several meters long, for example, in the common toad and the toad and contain several thousand eggs. The natterjack toad lays its spawn cords often from directly above shallow body of water.

Garlic toad ( Pelobates fuscus ) and other toads frogs produce relatively short spawning cords, which may be almost an inch thick. It is anchored between vertical structures ( plant stems, etc.) under water. Toads (Bombina ) lay single eggs or small spawning groups of 30 or fewer eggs on plants or on the seabed.

The obstetrician toads ( Alytes ), the males squirm when mating the spawning ropes the hind legs and carry him until hatching of the tadpoles around with you.

The females of newts (Triturus ) as representative of the salamanders attach their eggs singly on plants under water on by the females actively fold with the hind legs an " egg bag " and they stick to the Eigallerte. In contrast to anurans in which the insemination of the eggs takes place after exit from the cloaca, fertilization takes place at the newts already inside the body, according to a complex mating game instead.