Earthworms are one of the most ancient inhabitants of planet Earth. They live almost everywhere, with the exception of the permafrost of Antarctica. Thanks to this boneless creature, the soil becomes fertile. Their vital activity is the fundamental factor for the formation of the fertile layer.
General characteristics and living conditions
The body shape of the earthworm, its color, its dimensions are unique characteristics of the invertebrate. Let's consider in more detail.
The body of a worm is a multitude of ring-shaped segments. In some individuals, their number reaches 320. Worms move with the help of short setae located on these segments. Externally, the body of individuals resembles a long tube.
For their normal functioning, the humidity level should be at the level of 75%. Worms die if the earth dries up and humidity drops to 35% or lower. This is due to the fact that they breathe through the skin. Therefore, they simply cannot live in dry soil and in water.
The most optimal temperature for their comfortable life - from 18 to 24 degrees above zero. If it starts to get colder, then the worms begin to sink deeper, where it is warmer and more humid. If the atmospheric temperature does not rise, then they hibernate. If this figure rises above 42 degrees, then the worms die. The same thing happens if the temperature is too low. And the worms crawl out after the rain due to a lack of oxygen in the ground.
An interesting fact: it was the ability to fall into a state of suspended animation that allowed the worms to survive in the ice age.
The benefits of worms
Thanks to worms, the soil throughout the planet is in constant motion. The lower layers rise upwards and are saturated with carbon dioxide, humic acids. Thanks to these invertebrate animals, potassium and phosphorus enter the soil.
Worms better than any human hands and equipment prepare the ground for the growth of plants. Thanks to these creatures, even large stones and objects eventually sink deep into the ground. And small stones are gradually rubbed in the stomach of worms and turn into sand. However, the excessive use of chemicals by humans in agriculture inevitably leads to a reduction in their population. To date, the Red Book of Russia already contains 11 species of earthworms.
Color
The color of the earthworm directly depends on skin pigments. But this characteristic is relevant exclusively for living individuals.
If the worm does not have skin pigments, then it has a pink or red color throughout its life. With this component, the color of the earthworm can be brown, blue, yellow, or brown.
For example, the worm Allophora chlorotica has a yellowish or greenish color. And Lumbricus rubellus - earthworms - are brown-red or purple with a pearly shimmer.
Body length
The average size of all individuals is from 5 to 20 centimeters, with a thickness of 2 to 12 mm. However, invertebrates up to 3 meters in length are found in tropical forests. Naturally, with such sizes of ring-shaped segments, there can be more than 3 thousand.
Types of Worms
Invertebrate animals live in all layers of the soil, from which they distinguish species that feed on the surface of the earth:
|
Feeding on the surface |
Feeding in the soil |
||
|
Litter |
Under no circumstances do individuals fall below 10 centimeters into the ground |
Digging |
Dwelling in deep soil layers |
|
Soil-litter |
They live at a depth of 10 to 20 centimeters |
Burrows |
Constantly form new moves, but feed on the humus layer |
|
Burrows |
They make constantly deep moves, but only the upper end of the body can go outside, for food consumption and mating |
||
Litter and burrowing individuals are characteristic of waterlogged soils. In other words, they live near ponds, marshes and in regions with a humid subtropical climate.
The tundra is characterized by soil-litter and litter worms. In the steppes you can meet exclusively soil species.
The nutrition of the worms and digestive organs
Regardless of the type and color of the earthworm, they are all omnivores. By swallowing a huge amount of land, they absorb half-rotten leaves. From this mixture they get useful substances. They do not use only leaves with an unpleasant odor, but they like fresh ones.
C. Darwin wrote about the omnivorousness of worms. He conducted many experiments, hanging pieces of various foods, including the remains of dead worms, over the pot of animals, and most of this food was eaten.
After digesting the soil, the worm rises out and throws it out. Excrement saturated with intestinal secretions is viscous, and after drying in the air harden. There is no randomness in their actions, first the waste is dumped on one side, then on the other. As a result, a characteristic entrance to the mink, similar to a turret, is formed.
Worms not only feed on leaves, plant stems, shreds of wool, they use them to plug holes in holes.
In all, regardless of body shape and color, earthworms, the mouth is located on the front end of the body. The process of swallowing occurs due to the muscular pharynx. After this, food - land with leaves - enters the intestines. If some part of the food has not been digested, then it is thrown away with the processed one. The ejection occurs through the anus located on the posterior end of the body.
Reproductive system
All earthworms are hermaphrodites. Before laying eggs, two different individuals exchange seminal fluid, a light touch. After that, each worm from the “girdle” located on the front of the body releases mucus into which the eggs enter. After some time, a lump with them almost slides off the body and turns into a cocoon. After maturation, young individuals emerge from it.
Nervous system and sensory organs
Absolutely all individuals, regardless of the color of the earthworm, do not have sense organs. They have the best sense of touch. Such cells are located throughout the body, and even a slight vibration of the soil causes the worm to hide and sink into deeper layers of the soil. These elements are also responsible for the perception of light. After all, such individuals have no eyes. But if you illuminate them with a lantern at night, they will quickly hide.
Researchers claim that worms have a nervous system. This is confirmed by the fact that they have elementary reflexes: when you touch the body, it instantly contracts, protecting the worm from touching.
Even Darwin noticed that such creatures distinguish leaf species by smell. If the worms do not like the aroma of food, then he will refuse such a dinner.
Enemies of the animal
It does not matter what kind of body color the earthworm has, what kind of species it is and where it lives, all individuals have natural enemies. The worst of them is the mole. This mammalian animal not only eats worms, but also stores them for the future. The mole in saliva has a paralyzing substance that acts specifically on invertebrates. Thus, he catches worms.
Frogs and shrews will not disdain to taste them. Many birds eat earthworms - these are thrushes, poultry, starlings and woodcocks. Many arthropods do not disdain worms - they are arachnids, different types of insects and millipedes.
