The European nightcrawler (''Dendrobaena hortensis'') is a medium-small

earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...

averaging about 1.5 g when fully grown. Generally blueish, pink-grey in color with a banded or striped appearance, the tips of their tails are often cream or pale yellow. When the species has not been feeding, it is pale pink. The species is usually found in deep woodland litter and garden soils that are rich in

organic matter Organic matter, organic material or natural organic matter is the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come fro ...

in European countries. ''D. hortensis'' is sold primarily as a bait worm, but its popularity as a

compost Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical, and biological properties. It is commonly prepared by Decomposition, decomposing plant and food waste, recycling organic materials, and man ...

ing worm is increasing. It was considered part of '' Eisenia'' until 2003. It is also formerly considered part of the similar '' Dendrobaena veneta'', but now just part of the

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

. Both are useful compost worms. The two species are probably not distinguished in

vermicomposting Vermicompost (vermi-compost) is the product of the decomposition process using various species of worms, usually Eisenia foetida, red wigglers, Enchytraeus buchholzi, white worms, and other earthworms, to create a mixture of decomposing vegetable ...

. In general, the ''E. hortensis'' name is more common in North America while the ''D. veneta'' name is more common in Europe.

Etymology

The former genus ''Eisenia'' is named after Swedish scientist Gustav Eisen. According to the

International Code of Zoological Nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted Convention (norm), convention in zoology that rules the formal scientific name, scientific naming of organisms treated as animals. It is also informally known as the I ...

, the

specific Specific may refer to: * Specificity (disambiguation) * Specific, a cure or therapy for a specific illness Law * Specific deterrence, focussed on an individual * Specific finding, intermediate verdict used by a jury in determining the final ...

name ''hortensis'' ("of the garden") is derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''hortus'' meaning "garden". The other specific epithet ''veneta'' refers to the Veneto region of northern Italy.

Usage

Compared to ''

Eisenia fetida ''Eisenia fetida'', known under various common names such as manure worm, redworm, brandling worm, panfish worm, trout worm, tiger worm, red wiggler worm, etc., is a species of earthworm adapted to Decomposition, decaying organic material. These ...

'', ''D. hortensis'' does best in an environment with a higher carbon to nitrogen ratio. This makes it well suited to compost pits high in fibrous materials commonly known as browns. European nightcrawlers can be invasive and should be used only in contained compost systems in parts of the world with northern deciduous and boreal forest ecosystems.

Reproduction

''D. hortensis'', as a

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

, has both male and female reproductive organs. In mating, the weaker partner is forced into the female role, which is more expensive in terms of biological reproduction costs, for a

sperm cell Sperm (: sperm or sperms) is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail k ...

is generally less massive and energy-demanding than an

ovum The egg cell or ovum (: ova) is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is not capa ...

(egg cell), which is the female

reproductive The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are al ...

cell (

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

) in

anisogamous Different forms of anisogamy: A) anisogamy of motile cells, B) 283x283px Anisogamy is a form of sexual reproduction">egg cell">oogamy (egg cell and sperm cell), C) anisogamy of non-motile cells (egg cell and spermatia).">283x283px Anisogamy is ...

organisms. Two worms join clitella, the large, lighter-colored bands that contain the worms' reproductive organs, and are only prominent during the reproduction process. The two worms exchange

sperm Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm ...

. Both worms may secrete cocoons that contain an egg each. These cocoons are lemon-shaped and are pale yellow at first, becoming more brownish as the worms inside become mature. These cocoons are clearly visible to the naked eye. ;Statistics: * From egg to sexual maturity is about 20 weeks. * Net reproduction of 0.8 eggs per adult per week occurs. * Egg cells are oviposited in a cocoon. * One ''E. hortensis'' embryo per egg per cocoon occurs.

References

Lumbricidae Animals described in 1890 {{annelid-stub