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A dew worm (Lumbricus terrestris) leaving its living tube (evening - 8 p.m.)

A dew worm ( Lumbricus terrestris ) leaving its living tube (evening - 8 p.m.)

Over trunk : Lophotrochozoa (Lophotrochozoa)
Trunk : Annelids (Annelida)
Class : Belt worms (Clitellata)
Subclass : Little bristle (Oligochaeta)
Order : Earthworms in the broader sense (Crassiclitellata)
Family : worms
Scientific name
Rafinesque-Schmaltz , 1815
An earthworm in the humus topsoil

The earthworms (Lumbricidae) are articulated worms living in the ground from the order of the little bristle (Oligochaeta). They belong within the tribe of annelids (Annelida) to the class of belt worms ( Clitellata ). In 2008 about 670 species of earthworms (of the Lumbricidae family) were known worldwide. In addition, an unknown number of morphologically indistinguishable cryptospecies is suspected.

There are currently 46 species living in Switzerland and Germany, 54 in Austria. Not all of the species living in Europe are originally native there. Their average lifespan is between three and eight years. The 9 to 30 centimeter long dew worm or common earthworm ( Lumbricus terrestris ) is probably the best-known indigenous species of annelids , along with the 6 to 13 centimeter long compost worm ( Eisenia fetida ).

While the allocation in Europe is relatively clear, there are numerous other annelids from other families in other parts of the world that have a comparable way of life and are also called earthworms. The entire group is related to each other and probably monophyletic . It is named after a morphological feature, the multi-layer clitellum , Crassiclitellata . In addition to the lumbricoids It includes the families Acanthodrilidae , megascolecidae , Octochaetidae , Ocnerodrilidae , Eudrilidae , Hormogastridae , Lutodrilidae , Ailoscolecidae , Sparganophilidae , Glossoscolecidae , Kynotidae , Almidae and Microchaetidae , some of these families are taxonomically controversial in its delineation and independence. If an animal is referred to as an "earthworm", it can also belong to another Crassiclitellata family outside of Europe.


The origin of the term "earthworm" is controversial. According to one opinion, it is said to go back to the Old High German term "Regnwurm", which refers to the behavior of the worms to quickly leave the underground living tubes in heavy rainfall in order to escape the rising water in the topsoil on the earth's surface. According to another opinion, the German name derives from their constant underground activity; It is said to have been known as the "active worm" in the 16th century.

On the other hand, the actual location of the worm is related to the English term “earthworm”, where “rain worm” is also used, the Turkish “yer solucanı” and the French term “ver de terre” (earth worm).



Bristles magnified through a microscope

The body of the earthworm consists of numerous cylindrical members ( segments ) on the outside of its sides which hardly from the skin excellent bristles wear. The bristles, of which earthworms have four pairs per segment, consist of chitin and proteins and can be moved with the help of special muscles. The number of segments increases with the age of the worm. A special growth zone near the rear end produces new links. Adult specimens reach around 160 segments.

Cutaneous muscle tube

The entire body of the worm and thus also each of its segments is delimited to the outside by a skin muscle tube . A single layer of epidermis , which contains some glandular and sensory cells and is surrounded on the outside by a cuticle containing collagen , is followed by a layer of circular muscle. The thick longitudinal muscle layer connects to this in turn. Most species have skin pigments. For example, many Lumbricus species are more or less colored red. On the other hand, all Allolobophora species have more dark pigments, which make the skin surface appear light gray or gray-black.

Digestive organs

A kind of upper lip, also called the head flap ( prostomium ), arches over the mouth at the head end. The mouth opening leads into the intestine , which completely pulls the earthworm through from front to back. The intestine begins with the muscular pharynx , followed by the esophagus ( esophagus ) with its calcareous sacs, as well as a muscular goiter and gizzard. Here (similar to chickens ) the vegetable food is ground evenly by small stones (here grains of sand) that have been picked up. This is followed by the long midgut, which has an invagination ( Typhlosolis ) on the back over its entire length , which helps enlarge the inner surface of the intestine. At the back of the worm is the anus. With the help of calcium-containing deposits, the worms neutralize all acidic soil constituents they have absorbed and thus naturally improve the soil.


Between the internal organs and the skin muscle tube in each segment on the right and left is a cavity filled with fluid and surrounded by elastic, delicate skin, the secondary body cavity ( coelom ). The delimiting transverse and longitudinal walls in the segments are known as dissepiments or mesenteries . The trapped fluid acts as a hydrostatic skeleton for the invertebrate organism . In cooperation with the skin muscle tube, it supports the worm both when drilling in the ground and when moving in general, e.g. B. when crawling on the ground surface or in the living tube.

Excretory organs

The excretory organs begin at the back in each Coelom sac of the segments (with the exception of the first three limbs and the last segment) to the left and right of the intestine with one eyelash funnel each, the so-called nephridia . In the next Coelom sac, these pass into a long excretion canal, wound in loops, surrounded by blood vessels, which widens in the end section to form a urinary bladder. The eyelash funnel sucks in Coelom fluid, the largest part of which is transported into the blood in the excretion canal (apart from the waste materials). The veins also serve to supply the excretory organ with oxygen and nutrients. This supply of the cells is necessary because active transport processes for the excretion of uric acid , urea , ammonium and salts as well as for the absorption of water , ions and organic compounds take place on the loops of the nephridium .

Reproductive organs

As hermaphrodites, earthworms have both female and male genital organs and these also have both sides. They begin with two pairs of testicles in the front of the coelom of the 10th and 11th segment, packed in the so-called seed pods. The seed capsule of the 10th segment has two paired protuberances of the dissepiments in the anterior and posterior longitudinal direction, the seed pockets. The seed pocket of the 11th segment protrudes into the 12th segment. The matured sperm from these three pairs of seed bags migrate back into the seed capsules. Here, the sperm conductors begin with an eyelash funnel (an opening with a border of cilia that beat towards the inside), unite on both sides and open outwards in the 15th segment in two recognizable openings (male porus). The female organs ( ovaries and fallopian tubes ) are located in the 13th segment . The fallopian tubes open outwards in the 14th segment. There are also two pairs of semen pouches ( Receptacula seminis ) in the 9th to 10th segment for receiving sperm during mating.

Nervous system

Drawing with markings of the individual areas
Longitudinal section through the front end
bm = abdominal marrow
d = intestinal lumen with food particles
ep = epithelium
lm = longitudinal muscles
m = mouth opening
osg = upper pharyngeal ganglion
rm = circular muscle
usg = lower pharyngeal ganglion

The nervous system is highly developed. It is divided into the brain or upper pharyngeal ganglion , the abdominal medulla, and the segmental nerves . The brain, consisting of two fused cerebral ganglia, lies in the third segment just before the beginning of the pharynx dorsal to the intestine. Numerous nerves pull forward from it in the direction of the prostomium . Pharyngeal connectors connect the upper pharyngeal ganglion on both sides of the foregut with the sub- pharyngeal ganglion at the beginning of the fourth segment anterior to the intestine (see figure opposite). This is followed by the main strand of the nervous system, which runs through the worm on the belly side from the fourth head segment to the tail segment. It is therefore called the belly marrow. In a frontal section through the abdominal medulla one can see that it is evolutionarily derived from the rope ladder nervous system. The original organization of the rope ladder nervous system consists of paired connections running longitudinally to the body axis, which are connected to one another by commissures arranged transversely to the body axis . The connective and commissures are connected by nerve nodes ( ganglia ), which mainly consist of the cell bodies of the nerve cells. In the earthworm, these elements are all united in a median (unpaired) nerve cord. In histological specimens stained with azan , the two fiber components (commissures and connective) as well as the nerve nodes can be clearly differentiated on suitable sections.

In each segment, three pairs of segmental nerves branch off from the abdominal medulla. The front pair lies in the cranial (head-facing) section of a segment; the middle and the back pair are usually close together in the caudal (tail-oriented) area of ​​a segment. In the vast majority of cases, this typical arrangement allows a histological specimen to be oriented towards the head / tail. After branching off from the abdominal medulla, the segmental nerves first run through the earthworm's secondary body cavity (Coelom) and then enter the skin muscle tube, where they separate into a ventral and a dorsal branch. In their further course between the circular and longitudinal muscles, fine fibers continuously branch off and innervate the muscle cells and the cells of the epidermis.

The innervation of the dissepiments , i.e. the muscular partitions between the segments, is carried out by the so-called septal nerves, which branch off from the abdominal marrow in the armpits of the anterior segmental nerves.

The earthworm's intestinal nervous system, also known as the stomodaeal system, was discovered relatively late. Eyes are missing, but the earthworm is particularly sensitive to light at the front and rear ends. Individual photoreceptor cells are found in the epidermis. Thus the earthworm is at least able to differentiate between light and dark. The earthworm also reacts to vibrations in the ground.

Vascular system

The earthworm does not have any special respiratory organs, but it does have a multi-branched, closed blood vessel system that distributes the oxygen and nutrients absorbed from the intestines throughout the body. It consists of a dorsal vessel that drives the blood from the back to the front and an abdominal vessel. In segments seven to eleven, the two main blood vessels are connected by muscular and strongly contractile loops, the so-called lateral hearts (two per segment). In the remaining segments, there is no direct connection between the back and abdominal vessels via ring vessels, but via side vessels that branch out into capillaries in the organs and in the skin muscle tube and then reunite. The blood itself is colored red by the red blood pigment hemoglobin , which is dissolved in the blood plasma. In the skin capillaries, the blood releases carbon dioxide into the air and absorbs oxygen, which is bound to the hemoglobin, but also partially dissolves directly in the water of the blood ( skin breathing ); conversely, this gas exchange takes place in the capillaries of the internal organs. In order to ensure skin respiration, the skin must remain moist. So the earthworm can also survive in oxygen-rich water. The blood also contains colorless blood cells , the amoebocytes , which, however, mostly lie against the vessel walls. The hemoglobin of the earthworm does not consist of only 4, but of 24 subunits like that of humans. The molar mass of 3,840,000 g · mol −1 is correspondingly high .

Typical family characteristics of the Lumbricidae within the Crassiclitellata

The earthworms of the Lumbricidae family, like most Crassiclitellata (earthworms in a broader sense), have cylindrical bodies, sometimes with a flattened body end, sometimes with a square, octagonal or trapezoidal cross-section. Most lumbricids have dorsal pores, small openings on the back in which the coelom opens outwards and with which water can be released or absorbed.

The lumbricids do not have a gizzard in the esophagus, but a gizzard in the midgut, which occupies 1 to 2 segments between the 17th and 20th segment. Before that, a goiter sits in a single segment between the 15th and 17th segments. The animals have calcified glands in their foregut wall in some or all segments between the 10th (sometimes 9th) and the 15th segment. The large nephridia are well developed.

The lumbricid clitellum is usually saddle-shaped and occupies 4 to 32 segments between the 17th and 52nd segments. It also has a ribbon-like or papilla-like pubertal tubercle . According to the basic plan of the Crassiclitellata, the lumbricids always have two pairs of testes in the 10th and 11th segment (Holandrian), but behind only one pair of ovaries in the 13th segment (metagyn), of which the two fallopian tubes lead to the pair of female genital openings on the abdomen 14. Lead segment. The sperm conductors, on the other hand, come together to form a pair, coming from the four testes, cross several segments, including the one that carries the ovary, and thus lead to the pair of male genital orifices, which are located behind the female abdomen on the 15th segment, rarely on the 13th or 14th segment Segment still located in front of the clitellum. The paired, adiverticulate (no blind sacs) receptacula seminis are either interparietal or spread freely into the coelom and open through paired openings in 2 to 8 furrows between the transitions from the 5th to the 6th segment and from the 19th to the 20th segment outside, usually 2 pairs of openings in the two furrows between the 9th and 11th segment.

Regeneration after mutilation

Regenerative capacity

Earthworms have a remarkable ability to regenerate . It is thus possible for the animals to develop their rear end almost completely again after being severed, with the ability to regenerate decreasing towards the middle of the body. At the anterior end, depending on the type, a maximum of the first four to eight segments and the prostomium in front of the mouth opening can be separated. These segments are replaced again. The regeneration of the brain located in the 3rd segment ( upper and lower pharyngeal ganglion ) was investigated in the earthworm Dendrobaena veneta (syn. Eisenia hortensis ). If the brain is missing, the formation of gametes is inhibited, but it is restored by regeneration of the brain. The gonads ( testicles in the 10th and 11th segment, ovaries in the 13th segment) cannot be formed again after loss. If you cut off more segments at the front, not all of them are regenerated. If more than 15 segments are removed, regeneration of the front end is usually no longer possible. The regenerated material stands out clearly from the neighboring body part due to its lighter color.

The widespread rumor that if you cut a worm in half would create two living worms, it is not true. Every segment of the body has the genetic make-up to rebuild the anus, but not the head. Occasionally in some species a worm with two anus emerges from the cut rear end after being severed, which then starves to death sooner or later, depending on the number of remaining segments. The front end can only survive if the earthworm divides behind the 40th segment. In front of it are vital organs such as the lateral hearts, which are necessary for maintaining blood circulation and which lead to death if lost. Due to wound infections, only a few severed earthworms survive in the wild.

During regeneration, the earthworms go into rigidity. This makes use of moles , which bite into the foremost segments in order to store the immobile earthworms in chambers as a supply.


The worms are also able to mutilate themselves ( autotomy ) in certain dangerous situations , e.g. B. if it has been seized by a predator. Here, the worm ties up a number of segments at the rear end and leaves them to the predator to escape with the rest of the body.

Way of life


Photo of the ground dug up along a pipe (section)
Deep, vertically cut earthworm tube

The earthworms can be divided into three groups:

  • Epigeic species live just below the soil surface in the organically enriched horizon above the mineral soil. They live mainly on animal excrement and dead plant material. Due to the necessary UV protection, they are colored dark.
  • Anectic or anözische forms are vertical digging and also seek out deeper soil layers (2 m and more). These types promote the mixing of the mineral earth with the humus.
  • Endogeic representatives of earthworms live in the upper part of the mineral soil. They are translucent pale in color as they rarely come to the surface.

Earthworms can only survive anoxic conditions (completely without oxygen) in water-saturated soils for up to about two days. They are therefore absent in soils saturated with groundwater. Even wet and acidic peat soils are not colonized. Typical earthworm species in water-saturated soils are Octolasium tyrtaeum and Proctodrilus antipae .

Although mostly terrestrial, there are also some aquatic earthworms that inhabit stagnant and flowing waters. The only earthworm species that is common and widespread in Europe and lives aquatic and in water-saturated soils is Eiseniella tetraedra . This species occurs, for example, widespread in the river bed of the Rhine.


Leaves partially pulled into the ground (right) and excretions (left center) from earthworms

The nocturnal earthworms are mainly substrate and herbivores. That means that they fill their intestines with humus-rich soil and rotten plant material. At night, for example, they pull seedlings and leaves into the ground to rot and later use as food. In order to hold the leaves in place, earthworms can inflate their front end like a button so that their mouth is surrounded by a suction cup. This is pressed against the leaf or the petiole and with the help of the muscular pharynx the worm sucks itself so tightly that it is able to crawl backwards and pull the sucked leaf into its living tube. Secretions from the pharyngeal glands promote the decomposition process. The ingested food is then ground up with the help of the gizzard and digested in the midgut.

The earthworms are constantly eating their way back and forth through the soil layers of their living area. The soil ingested contains detritus components, bacteria, fungal spores and numerous single-cell organisms that can be digested and used as food. Some species also eat carrion. Due to the nature of the earth, which the earthworm creates when it has excreted the soil components that it has eaten with it, the microorganisms useful for the soil are promoted and the ones that are hostile to the soil are contained, e.g. T. even destroyed.

Locomotion and digging

Circular and longitudinal muscles in motion, as part of locomotion

With the help of its bristles and the ring and longitudinal muscles, the earthworm is able to crawl both forwards and backwards. For example, if the bristles are directed backwards when crawling, the contraction of the sphincters at the front end makes it thinner and longer. The bristles anchor the rear segments in the ground, while the front part slides forward across the ground. This is followed by a front-to-back contraction of the longitudinal muscles, making the segments thicker and shorter again, pulling the worm body forward ( peristaltic movement ). Touch and light stimuli can also cause earthworms to rapidly contract muscles in the sense of an escape reaction .

Earthworms form tubes as they migrate through the soil. In a loose soil substrate such as moist forest soil or compost soil, the animals have no problems penetrating the soil. Mineral floors, on the other hand, offer very different levels of resistance depending on the grain size, strength and current water content. The thinned front end is used as a drilling instrument when penetrating the topsoil and when building new underground living tubes. The stable hydrostatic pressure of the body cavity fluid serves to overcome the soil resistance.

Usually the drilled tubes are lined all around with mucus and excrement of the worms and thus stabilized for the rapid ascent and descent. This solidification is also called "wallpaper". It also serves as a fertilizer for the plants.


Photo of two copulating earthworms attached to one another
Copulation - the clitellum is clearly visible in both worms.
Cocoons of Lumbricus terrestris

Sexual maturity, which occurs at one to two years of age, is shown by the formation of the so-called belt ( clitellum ), a yellowish saddle-shaped, glandular thickening from the 27th to 35th segment. The lateral margins of the clitellum are particularly prominent as so-called puberty ridges.

Earthworms are hermaphrodites and mate with one another. Large glands of the belt excrete a secretion during copulation , with which each worm attaches itself in opposite directions to the ventral side of the 10th segment of the other partner. Then each worm secretes a clearly visible portion of sperm from the two sperm conductors, which it transports by moving the skin along two seminal grooves in the direction of its belt to the partner's seminal pouches ( Receptacula seminis ). The foreign sperm stored there are used a few days later to fertilize your own egg cells. Self-fertilization has occasionally been observed in some earthworm species.

The eggs (as with the leeches ) are laid in cocoons . One clitellum secretion serves to form the shell of this egg cocoon, a second fills it with a layer of protein . Then the worm pulls backwards out of the cocoon ring, into which one or more eggs are released from the fallopian tube mouths, depending on the species, and sperm cells from the seminal bags. The embryos feed on the protein that surrounds them and, after a brief trochophoric phase, undergo metamorphosis in the egg into an initially transparent worm.

The development time of young worms can vary greatly depending on the species and the ambient temperature. The compost worm ( Eisenia fetida ) hatches in its relatively warm environment after 16 to 20 days, whereas Lumbricus terrestris needs up to 135 days at a mean soil temperature of around 12 ° C.

Behavior in heat and cold

The temperature optimum for most earthworm species is 10 to 14 ° C (compost worms: 20–25 ° C). They also need moist soil. This means that earthworms are less active or not at all active in summer and winter.

In Central Europe, earthworms spend the winter months (December to February) at a depth of 40 to 80 cm in a kind of rigid cold . Often there are whole colonies of curled worms under heat-storing soil structures such as tree stumps, stones or compost heaps. Under high and tightly closed snow cover, the ground is protected against the cold and usually not frozen. In places you can observe earthworms that are active in the topsoil even in winter. It is still unknown to what extent and for how long the animals can survive degrees of cold. In the medium term, the worms that are active in winter run the risk of drying out, as the soil is not soaked due to the frozen snow cover or soil surface. Some species can lose about 80% of their original weight during hibernation before they die. Lumbricus terrestris, for example, does not really hibernate in the relatively mild areas of southwest Germany ( Upper Rhine Rift ). It always appears on the surface of the soil on damp, frost-free nights to take in food.

The cocoons of sexually mature earthworms deposited in autumn continue to develop in the frost-free soil over the winter. In spring, the young worms hatch after a soil temperature of over 10 ° C.

Escape to the surface when it rains

Earthworms have fled to the surface
Earthworms that have fled to the surface after continuous rain

Why the earthworms leave their living tubes when it rains is not yet fully understood. It is often assumed that the earthworms do not crawl to the surface of the earth because they love the humid environment of the precipitation, but because they would suffocate in their tunnels in the ground when it rains, especially during long periods of rain, because the oxygen dissolved in the water is insufficient, to provide the worm with enough oxygen through skin respiration . However, scientific studies have shown that even under anaerobic conditions, earthworms kept under water only slowly perish after 35 hours. As it turned out, under these extreme conditions, the worms switch to a glycolytic metabolism without consumption of oxygen ( lactic acid fermentation ). Earthworms are able to survive floods with oxygen-rich water for up to several months. In fact, they even reach unusually high settlement densities in floodplains that are often flooded.

A study by Carleton University in Ottawa, Canada, suggests that earthworms crawl to the surface for fear of moles: In America, it is common for anglers to grunt earthworms by means of "worm grunting" (substrate sound generated by a stick and a vibrating metal disc) out of the ground, the sound resembles the digging sound of moles, important predators of earthworms. Falling raindrops are said to generate similar frequencies, which the worms may mistake for burrowing moles. A second study in Florida produced comparable results. It is unclear whether these results, obtained on the American Diplocardia mississippiensis , Diplocardia floridana and Pheretima diffringens , family Acanthodrilidae , are generally valid. Lumbricidae do not seem to react in a comparable way to substrate noise.

Importance for soil improvement

Role as destructor

Photo of an earthworm in the ground (cut)
Earthworms provide aeration for the soil.
forming excretions from French earthworms (from Darwin's The Formation of Soil by the Activity of Worms ). According to Louis Pasteur , earthworms also bring the spores of anthrax bacteria back to the surface from buried animal carcasses in this way .

In certain areas, earthworms can account for up to 90 percent of the biomass of the total soil fauna, with the worm density reaching up to 2000 individuals per square meter. As destructors, they play a central role in the breakdown of organic substances. The air-containing passages of earthworms ensure that aerobic bacteria are supplied with sufficient oxygen and that dead plant parts are better broken down.

The targeted processing of compost ( composting ) by earthworms ( worm compost ) results in the so-called worm humus with highly concentrated components of plant-available nutrients.

In the plains in Colombia and Venezuela called Llanos , square kilometer landscapes of up to five meters wide mounds of earth, called surales , were created mainly by excretions of earthworms of the genus Andiorrhinus (family Glossoscolecidae ).

Aeration and mixing of the floors

The earthworms usually deposit their excrement above ground in the form of ringed excrement balls at the mouth of their tunnels. As early as 1881, Charles Darwin described in his book The Formation of Arable Soil Through the Activity of Worms, the fact that earthworms constantly carry the earth from the deeper layers of the soil through their intestines to the earth's surface and thereby contribute to loosening and aerating the soil. An accompanying effect is the easier penetration of water into deeper soil layers. This in turn promotes plant growth. In the vertically drilled tunnels, however, plant roots can also grow deeper more quickly.

According to Darwin's calculation, the earthworms in many parts of England carry a weight of more than 25,000 kg of soil to the surface on a six hectare piece of land and thereby cause a very considerable mixing of the soil layers, whereby the subsoil is enriched with humus substances . As a result of this activity, stones or lost coins “sink” into the ground, because the excretions that are deposited on the surface come from deeper soil layers. This process is commonly known as bioturbation . In the topsoil of the tropics and subtropics, significantly higher conversion rates were found. It is obvious that the soils of the tropical rainforest are at the top here (up to 280 t per hectare).

Also in 1881, Louis Pasteur had pointed out that in the excrement balls of earthworms, pathogens from deeper layers of the earth can reach the surface. At that time it was common practice to bury cattle , sheep and horses that had died from anthrax pathogens ( Bacillus anthracis ) in a field or meadow. High concentrations of anthrax pathogens had been discovered in the earthworms' excrement balls above these carcasses , which were detectably ingested by grazing animals and led to further infections. A year later, Robert Koch also discussed this form of infection in his publication "About Anthrax Vaccination".

The positive effects of earthworms cannot be measured in the field because they cannot be separated from other environmental influences. Under standardized conditions in the laboratory, however, the effects of their activities on soil improvement can be proven.

Organic horticulture

Earthworms are of central importance for organic horticulture. Earthworms are considered to be the most important producers of permanent humus , synonymous with the excretions of the earthworm, a stable soil structure, ideal for plant growth and with many nutrients available for the plants. Therefore, the care of the soil in the form of covering or superficial chopping against drying out, mulching and the introduction of compost is a benefit of the living conditions for the soil life ( Edaphon ) and thus for the earthworms.

The compost heap in organic horticulture imitates the digestive activity of the earthworm on a large scale. The compost worm and the red forest earthworm are particularly common here, as well as under mulch material. The maturity of the compost can be determined by the fact that the pile has collapsed and the earthworms have left it.

The nutrient enrichment by earthworms is generated indirectly through organic fertilization and artificial fertilizers are explicitly avoided. Since the burial activity of earthworms loosens the soil sufficiently, digging is no longer necessary in organic gardens, in contrast to conventional cultivation methods, if the soil is properly cared for.


Ground beetle ( Carabus auratus ) prey on an earthworm

Earthworms are a source of food for numerous bird species. Mostly starlings , thrushes and crows , in the north also increasingly gulls and oystercatchers , who specifically target the worms. Other natural enemies are martens , moles , hedgehogs , shrews , common toads , frogs , fire salamanders , centipedes , ants , ground beetles and land planarians . Even foxes and badgers like to feed on earthworms.

Moles often bite earthworms in the front end to prevent them from crawling away. The worms that are unable to escape in this way but are still viable are then deposited in a safe place under the earth as a food supply, for example for the winter months.


Numerous parasitic organisms live in earthworms. In addition to various, sometimes symbiotic bacteria , ciliates and flagellates , gregarines ( sporozoa ) and roundworms (nematodes) are particularly common . The body cavity and the seminal vesicle are particularly affected. Most parasites are harmless in nature, but some, as intermediate hosts, transmit serious diseases (for example, lungworm disease in pigs and chickens through species of metastrongyle ). Occasionally, tapeworm larvae ( Eucestoda ) are also found in earthworms. Occasionally, larvae of the gold fly ( Lucilia sericata ) parasitize in earthworms. They prefer to stay in the front area of ​​the earthworm (third and fourth segment) and lead to the death of their host after a while.

Hazard and protection

Earthworm in the soil profile
A black mold beetle attacks an earthworm

Comparatively little is known about the endangerment of individual earthworm species because the fauna is poorly known in most regions. Even for Germany, which has been well researched in terms of fauna, there is no red list yet . Numerous endangered endemic species with a small distribution area are known from the Balkan Peninsula, for example. From a global perspective, in addition to the agricultural use of former forests, the introduction of exotic species with displacement of the local fauna is one of the main risk factors. The species-rich fauna of the Caribbean islands is particularly threatened.

The density and frequency of earthworms depend on soil factors and land management. Earthworms are rare or absent from sandy soils with a low pH . In addition, their occurrence depends on the plant litter. Therefore, fewer earthworms live under coniferous forests than under deciduous forests, and they are particularly rare in eucalyptus forests.

Due to the influence on the soil structure and the decomposition of litter, a high density of earthworms is usually aimed for in agricultural soils. However, their density is extremely reduced by plowing , which specifically affects the large species. While organic fertilization, e.g. B. compost , are favorable, the spreading of liquid manure reduces their settlement density . Many pesticides have also been shown to have negative effects (particularly fungicides and insecticides ). For herbicides with the active ingredient glyphosate , a study published in August 2015 showed that the dewworm ( Lumbricus terrestris ) almost completely ceased its activity after herbicide application, while the meadow worm ( Aporrectodea caliginosa ) remained unabated. The use of herbicides also reduced the rate of reproduction in the meadow worm by 56%. High doses of copper-containing substances are particularly unfavorable . For a long time this was underestimated due to the low sensitivity of the compost worm Eisenia fetida used as a test organism, which does not occur in natural soils .

Worm breeding, worm farm

Most earthworm species can be kept in captivity relatively easily and reproduced accordingly. In this way, earthworms are grown on a large scale in so-called worm farms and used commercially. The worms are widely used as food animals in pet shops or as bait for the angler . Breeding approaches and accessories for breeding worms can be ordered from specialized companies on the Internet and sent by post.

For some time now, worm cultures have also been used for soil improvement and compost management. Species that naturally have high conversion and reproduction rates are best suited for this purpose, e.g. B. Eisenia fetida .

Recently, tropical earthworm species have also been cultivated in heated facilities, e.g. B. Eudrilus eugeniae from West Africa. Such species should only be grown in closed areas (greenhouses, laboratory units). However, because of the neozoa problem , they should not be brought into the field . For the hobby gardener and the keeper of terrarium animals (e.g. turtles , frog and tailed amphibians ), breeding earthworms in so-called worm boxes can be worthwhile. These special containers are u. a. also for installation on balconies and terraces.

Reports keep appearing in the press that earthworms are bred and offered for human consumption (e.g. as meatballs - so-called “wormburger” or freshly fried). Due to the generally strong parasitization of the worms, caution is advised here (see below, parasites ).

Fishing methods

Thielemann's octet method

The Thielemann octet method is a scientifically recognized application for catching earthworms using electric current. The method according to the biologist Ullrich Thielemann is often used in the context of studies for the standardized inventory of the earthworm fauna of special locations. It is also a widely used detection method in the course of biomonitoring . Eight electrodes are pushed into the topsoil in a circle at a distance of about 50 cm from one another. Depending on the conductivity of the existing soil, “chopped up” DC voltage pulses of 50 to 250 volts are applied to the electrodes for a period of around 20 minutes. Within a few minutes, the earthworms that live in the electric field are driven out of the ground, with the larger specimens usually crawling to the surface first.


Another and more common method for extracting earthworms from the ground is the use of formalin (formaldehyde). To obtain the animals, 50 ml of 37 percent formalin are mixed with 10 liters of tap water and the formalin mixture thus produced is distributed over about 1/2 m² of lawn or floor area. Immediately after being picked up, the animals obtained in this way are placed in clean tap water for about 10 to 15 minutes for slime. For the determination of the animals z. B. under a dissecting microscope , they are anesthetized with CO 2 gas after a recovery break of about two hours . Then the worms are placed on a prepared growing substrate, where they burrow after five to ten minutes.

Due to the health hazard posed by formalin, this method is not recommended.


As an alternative to the poisonous and environmentally harmful formaldehyde, mustard has also been recommended as a (and cheaper) expelling agent since the early 1990s . With this method, 60 g mustard flour is first added to half a liter of water. After an hour of waiting and thorough mixing, the suspension is poured into 9.5 liters of water. Ready-made mustard can also be used, which is easier to handle because it can be stirred directly into the water; however, here the expelling effect is less with regard to certain earthworm species (namely the genera Aporrectodea and Allolobophora ).

Other fishing methods

In certain regions of Canada, the United States and England, earthworms are heavily hunted with vibrations . The methods are called worm grunting , worm charming and worm fiddling .


The family Lumbricidae belongs to a clade of girdle worms (Clitellata), which is called Crassiclitellata after a morphological characteristic, the multi-layer clitellum . The Crassiclitellata correspond to the earthworms (or English earthworms) in the broader sense. They are (almost) worldwide, while Lumbricidae themselves only occur holarctic in Europe, parts of Western Asia and North America. According to phylogenomic data, both the Crassiclitellata and the Lumbricidae are monophyletic . The analysis of the relationships had been hindered for decades by the morphological monotony of the animals, their high evolutionary age, combined with the high rate of evolution in some subgroups, which later refuted numerous earlier systematic and taxonomic hypotheses. Several genera turned out to be polyphyletic embarrassment taxa assembled according to one characteristic, so they are not evolutionary units. This applies, at least, to the "genera" Allolobophora , Aporrectodea , Cataladrilus , Cernosvitovia , Dendrobaena , Helodrilus and Octodrilus , and possibly others.

Within the Crassiclitellata, a superfamily Lumbricoidea is distinguished which, in a revised version, includes the families Lumbricidae, Hormogastridae (including the monotypic Ailoscolecidae), Criodrilidae and Lutodrilidae . Most closely related, and probably sister groups , are the families Criodrilidae and Hormogastridae. The Criodrilidae are a small family with only one or two genera and probably only three species, with a Palearctic distribution, from the European Mediterranean region and North Africa to Japan. The Hormogastridae comprise four genera with almost 30 species, which are adapted to particularly dry soils, and live in the western Mediterranean area.

According to the genetic data, the Lumbricidae family originated in the Cretaceous . The earliest split-off species live in the western Mediterranean area and on the islands of Sardinia and Corsica, so that the origin of the family appears likely in Europe, where it is still most common today. The North American species would have colonized the continent before the split of the primary continent Laurasia . The oldest species all have an endogeic way of life within the ground. The Epigaean species living in the litter layer and the Anözian species alternating between the strata would accordingly be younger and derived from them.

Earthworms are not closely related to other animals known as " worms ". The term “worms” today only denotes a certain habitus, but no systematic unit.

Genera and species occurring in Germany

A total of 47 earthworm species from 15 genera have been identified in Germany, with the Baden giant earthworm ( Lumbricus badensis ) only being one endemic species. The number of species increases from north to south, 14 species occur exclusively in the south.

Over 670 species in over 40 genera are currently recognized in the earthworm family. They are divided into ecological groups and, according to the taxonomic classification of the previously cited investigation - limited to Germany - include the following genera and species:

Group of endogean earthworms (live in the upper mineral layer of the soil in horizontal tunnels): genus Allolobophora

Genus Aporrectodea ( syn.Allolobophora )

  • Gray Worm, Worm Small Burnet ( Aporrectodea caliginosa syn. Nicodrilus caliginosus )
  • Aporrectodea cupulifera
  • Aporrectodea georgii
  • Aporrectodea handlirschi
  • Aporrectodea icterica
  • Aporrectodea jassyensis
  • Aporrectodea limicola
  • Great Burnet worm ( Aporrectodea longa syn. Allolobophora longa syn. Nicodrilus longus )
  • Slime worm ( Aporrectodea rosea )
  • Aporrectodea thaleri

Genus Helodrilus

  • Helodrilus oculatus

Genus Murchieona

  • Murchieona minuscula
  • Murchieona muldali

Genus Octodrilus

  • Octodrilus argoviensis (found in bodies of water)
  • Octodrilus transpadanus

Genus Octolasion

  • Bluish earthworm ( Octolasion cyaneum )
  • Octolasion tyrtaeum

Genus Proctodrilus

  • Proctodrilus antipae
  • Proctodrilus tuberculatus

Group of the Anecian earthworms (live in the upper, up to three meters deep soil layers in vertical corridors): genus Aporrectodea

  • Aporrectodea longa

Genus Fitzingeria

  • Fitzingeria platyura

Genus Lumbricus

Group of the epigeic earthworms (live in an organic layer above the ground): genus Allolobophoridella

Genus Aporrectodea

  • Aporrectodea handlirschi
  • Aporrectodea smaragdina , in the Alpine region

Genus Dendrobaena

  • Dendrobaena attemsi
  • Dendrobaena auriculata
  • Dendrobaena hortensis (crop follower)
  • Dendrobaena illyrica
  • Stumpworm ( Dendrobaena octaedra )
  • Dendrobaena pygmaea
  • Dendrobaena veydovskyi
  • Dendrobaena veneta (follower of culture)

Genus Dendrodrilus

  • Quiver worm ( Dendrodrilus rubidus syn. Dendrobaena rubida )

Genus Eisenia

Genus Eiseniella

  • Eiseniella tetraedra

Genus Lumbricus

Genus Satchellius

  • Satchellius mammalis


The following genera belong to the Lumbricidae family :

Use as bio-indicators

Earthworms are also used in bioindication. They accumulate heavy metals in the soil in such a way that their uptake of the heavy metals correlates with the corresponding soil content. The monitoring of earthworms mainly serves to detect creeping changes in the soil. Since earthworms are at the beginning of a food chain, they are of great importance from an ecological point of view.

For the bio-monitoring with earthworms, a statistically sufficient number of earthworms is collected from an area of ​​approximately half a square meter . Sampling must be repeated annually at the same time.

Neozoa problem of European earthworms in the USA

In the north-east of the USA , the feeding behavior (presumably as fishing bait) of introduced European earthworm species has a negative effect on the soil ecosystem of the deciduous forests in places. Since there have been no earthworms since the last ice age, the deciduous forests have adjusted to the fact that thick layers of leaves form on the ground, which serve as insulation in winter and protect smaller plants and tree saplings from frost. But where earthworms - for example the dewworm and the red forest earthworm - decompose this layer, the soil and undergrowth are exposed to the severe frost of the North American winter. This can threaten native species and forest regeneration.

Faroe Islands postage stamp

Earthworms in Popular Culture

An earthworm is the unconventional video game protagonist Earthworm Jim , a shooting superhero who also got his own cartoon series. An earthworm named Max appears in the cartoon series “ Maya the Bee ”. Other video games starring earthworms are those in the Worms series.


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Web links

Commons : Earthworms  - album with pictures, videos and audio files
Wiktionary: earthworm  - explanations of meanings, word origins, synonyms, translations

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This version was added to the list of articles worth reading on August 21, 2005 .