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Eisenia fetida

Redworms or Eisenia fetida are the most common and widely used composting worms in the world. So, what makes them so popular? Join us as we try to find out.
Batul Nafisa Baxamusa
Eisenia fetida is a species of earthworm, which is widely used for vermicomposting. At 1½" to 2½" inches, it is the smallest of the earthworm species found in the world. These worms are generally raised by farmers and people who are into gardening, who use their compost as a fertilizer.
They are also used by fishermen as a bait for fishing trout, pan fish, etc. Additionally, people who own fish aquariums use these worms as fish food.
Eisenia fetida Facts
Common Name: Eisenia fetida is basically the binomial or scientific name of this species. (The term fetida means unpleasant or foul smelling, which is derived from the fact that these worms release a foul, pungent liquid when handled roughly.)
They are usually known by common names like redworms, brandling worms, red wiggler worms, tiger worms, manure worms, stink worms, fish worms, dung worms, fecal worms, striped worms, angleworms, bandlings, and so on.
Range and Habitat: Native to Europe, the species is now found on all the continents of the world; except for Antarctica. They thrive in areas with rotting manure, compost, vegetation, etc. As opposed to other worms, these worms are epigeal in nature, i.e., they are found above the soil or in the top soil.
Anatomy: Eisenia fetida has a long, tube-like body, which is typically slimy on the outside. It has a simple closed circulatory system and two main blood vessels. The digestive system is present within the tube.
The anatomy shows the body is formed of segments that are become specialized towards the anterior part. It can be differentiated from other worms by their alternating red and buff stripes.
Reproduction: Like all earthworms, this species is also a hermaphrodite, i.e., a species possessing both male and female reproductive organs. However, they cannot undergo self-fertilization, and therefore, need a mate to reproduce.
When two worms that have reached sexual maturity come together, they undergo copulation. They align themselves side by side, with their heads pointing the opposite direction, and secrete a mucous-like substance that helps them seal their bodies together. Eventually, the exchange of sperms takes place.
The sperms are deposited on their skin surface, from where they move towards a pore, few segments above the clitellum. Then, each individual worm secretes its own eggs, and these eggs get fertilized by the sperm of the other worm. The eggs are formed within little cocoons.
The worm can continue producing such cocoons as long as it does not run out of sperms from its partner. These eggs hatch after an incubation period of about 32 to 72 days and the young ones come out of the cocoons.
Redworms attain sexual maturity within 8 to 10 weeks of their birth. In ideal conditions, the species can produce two to three cocoons per week for 6 to 12 months. Add to it the fact that these worms have an average lifespan of 3 to 4 years, and the rapid rise in their numbers makes perfect sense.
Ideal Temperature: These worms require an optimum temperature of about 68° to 77° F (20° to 25° C). They can tolerate temperatures in the range of 40° to 80° F. However, they undergo severe stress if the temperature of their surrounding reaches 85° F, and die when the temperature reaches 90° F.
Buying Redworms: Ideally, you should buy these worms from a reputed source. A starter culture bag is sold for roughly about $24.95. If you buy 1 pound of redworms, you will have 10 pounds of worms by the end of 4 months; provided they are well fed with food that is at least 3 times their body weight.
Eisenia fetida species the easiest of all earthworm species when it comes to maintenance and thus, are very popular among farmers and gardeners.