Eisenia fetida is a small, fast-breeding earthworm of decaying organic matter. Known as the red wiggler, brandling or tiger worm, it is the species used in almost all small-scale vermicomposting.
1Description
Adults are reddish-brown with lighter, yellowish bands between the segments, which gives the striped look behind the name tiger worm. When handled roughly it releases a strong-smelling coelomic fluid, which is the origin of the species name fetida ("foul-smelling").
Like all earthworms it has no eyes, lungs or skeleton. It breathes through its moist skin and senses light with receptor cells concentrated at the front end.
2Ecology
E. fetida is epigeic: it lives in the litter layer on top of the soil rather than burrowing into it. In nature it is found in manure heaps, leaf piles and rotting wood, habitats that are rich in food but short-lived. This explains its fast reproduction and its tolerance for crowding, both of which make it ideal for worm bins.
3Reproduction
Each worm is a hermaphrodite but two are needed to mate. After mating, the clitellum (the thickened band near the front) secretes a cocoon that slides off over the head. A cocoon holds on average two to four embryos, which hatch after about three weeks at 20–25 °C.
Under good conditions a population can double in roughly two to three months.
4Use in vermicomposting
A healthy culture processes roughly half its own body weight of food per day. Keep the bedding as moist as a wrung-out sponge, avoid citrus, onion, meat and dairy, and feed in small amounts buried under the surface.