Potworms (or 'white worms') are small, white, segmented worms, related to earthworms. All oligochaete worms have small bristles (setae) in bundles on most body segments. In the Family Enchytraeidae, these setae bundles begin from the second segment and there are usually four setae on each bundle. All the setae are pointed, simple in structure, and are either straight or sigmoid (s-shaped).
25 mm long, diameter 0.7 mm - 1.5 mm.
Potworms are found in littoral (shore), aquatic and terrestrial habitats and frequently in moist forest soils. They can reach densities of 250,000 individuals per square metre. Although they are widely distributed, they are not common in the tropics.
Potworms have a thin cuticle, on the body surface, through which water can diffuse in and out. Because of this, they require 100% humidity and will dehydrate and die in dry environments.
Feeding and Diet
Potworms feed on dead organic matter and small droppings. They also ingest small mineral particles and may play an important role in mixing organic matter into the mineral soil. Close examination of a live potworm with a magnifier will reveal the movement of the food from the mouth to the anal opening at the rear end of the body.
Other behaviours and adaptations
Potworms are often encountered in compost bins and worm farms, particularly if these are slightly acidic. Like earthworms, they function as composters and will not harm healthy compost worms. Potworm numbers can be reduced by adding bread soaked in milk to the surface of the worm bedding material. When the bread is covered in white worms, it can be removed and replaced.
Recently, a soil toxicity test was developed using potworms as test animals. This is because potworms are:
- relatively easy to work with
- come into contact with both the soil solution and the solid parts of soil
- considered to be 'keystone' species in virtually all terrestrial ecosystems.
Some potworms are raised as fishfood.
Mating and reproduction
Oligochaete worms are hermaphroditic, meaning they possess both male and female reproductive organs. When oligochaete worms are in their reproductive phase, they have a ring of thickened, glandular skin (called a clitellum) around the genital segments. In potworms, the testes (male reproductive tissue) are in segment 11, the ovaries (female reproductive tissue) and male pore are in segment 12 and the paired spermathecae (sperm receptacles) in segment 5.
- Van Vliet, P. C. J., Coleman, D. C. and Hendrix, P. F. (1997). Population dynamics of Enchytraeidae (Oligochaeta) in different agricultural systems. Biology and Fertility of Soils 25: 123-129.
- Rob Blakemore, Tasmanian Earthworms CD-ROM.