Eisenia fetida

Eisenia fetida (older spelling: foetida), known under various common names such as redworm, brandling worm, panfish worm, trout worm, tiger worm, red wiggler worm, etc., is a species of earthworm adapted to decaying organic material. These worms thrive in rotting vegetation, compost, and manure. They are epigean, rarely found in soil. In this trait, they resemble Lumbricus rubellus.

Eisenia fetida
Scientific classification
Kingdom:
Animalia
Phylum:
Annelida
Class:
Clitellata
Order:
Haplotaxida
Family:
Lumbricidae
Genus:
Eisenia
Species:
E. fetida
Binomial name
Eisenia fetida
(Savigny, 1826) [1]

They have groups of bristles (called setae) on each segment that move in and out to grip nearby surfaces as the worms stretch and contract their muscles to push themselves forward or backward.

E. fetida worms are used for vermicomposting of both domestic and industrial organic waste.[2][3][4] They are native to Europe, but have been introduced (both intentionally and unintentionally) to every other continent except Antarctica. Tiger worms are also being tested for use in a flushless toilet, currently being trialled in India, Uganda and Myanmar.[5]

E. fetida also possess a unique natural defense system in their coelomic fluid: cells called coelomocytes secrete a protein called lysenin, which is a pore-forming toxin (PFT), which is able to permeabilize and lyse invading cells. It is best at targeting foreign cells whose membranes contain significant amounts of sphingomyelin. (Lysenin is also toxic to organisms lacking sphingomyelin in their cell walls, including B. megaterium, though the pathway is not understood). [6]

Odor

When roughly handled, a redworm exudes a pungent liquid, thus the specific name foetida meaning "foul-smelling". This is presumably an antipredator adaptation.

Close-up of E. fetida with visible bristles

E. fetida is closely related to E. andrei, also referred to as E. f. andrei. The only simple way of distinguishing the two species is that E. fetida is sometimes lighter in colour. Molecular analyses have confirmed their identity as separate species, and breeding experiments have shown that they do produce hybrids. [7]

Reproduction

As with other earthworm species, E. fetida is hermaphroditic, and uniparental reproduction is possible, even if usually the reproduction is between copulating individuals.[8] The two worms join clitella, the large, lighter-colored bands which contain the worms' reproductive organs, and which are only prominent during the reproduction process. The two worms exchange sperm. Both worms then secrete cocoons which contain several eggs 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.

References
  1. "Eisenia foetida". Fauna Europaea. 2004.
  2. Albanell, E.; Plaixats, J.; Cabrero, T. (1988). "Chemical changes during vermicomposting (Eisenia fetida) of sheep manure mixed with cotton industrial wastes". Biology and Fertility of Soils. 6 (3). doi:10.1007/BF00260823. ISSN 0178-2762.
  3. Orozco, F. H.; Cegarra, J.; Trujillo, L. M.; Roig, A. (1996). "Vermicomposting of coffee pulp using the earthworm Eisenia fetida: Effects on C and N contents and the availability of nutrients". Biology and Fertility of Soils. 22 (1–2): 162–166. doi:10.1007/BF00384449. ISSN 0178-2762.
  4. Maboeta, M.S.; Rensburg, L.van (2003). "Vermicomposting of industrially produced woodchips and sewage sludge utilizing Eisenia fetida". Ecotoxicology and Environmental Safety. 56 (2): 265–270. doi:10.1016/S0147-6513(02)00101-X. ISSN 0147-6513.
  5. "Testing the "Tiger Toilet"". US AID. May 26, 2016.
  6. Bruhn, Heike; Winkelmann, Julia; Andersen, Christian; Andrä, Jörg; Leippe, Matthias (2006-01-01). "Dissection of the mechanisms of cytolytic and antibacterial activity of lysenin, a defence protein of the annelid Eisenia fetida". Developmental & Comparative Immunology. 30 (7): 597–606. doi:10.1016/j.dci.2005.09.002. ISSN 0145-305X.
  7. Plytycz, Barbara; Bigaj, Janusz; Panz, Tomasz; Grzmil, Paweł (2018-09-21). "Asymmetrical hybridization and gene flow between Eisenia andrei and E. fetida lumbricid earthworms". PLOS ONE. 13 (9): e0204469. Bibcode:2018PLoSO..1304469P. doi:10.1371/journal.pone.0204469. PMC 6150523. PMID 30240427.
  8. Domínguez, Jorge; Velando, Alberto; Aira, Manuel; Monroy, Fernando (2003-01-01). "Uniparental reproduction of Eisenia fetida and E. andrei (Oligochaeta: Lumbricidae): evidence of self-insemination: The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002". Pedobiologia. 47 (5): 530–534. doi:10.1078/0031-4056-00224. ISSN 0031-4056.
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