Black Worm II

Black Worm II


Raising and Handling

California blackworms can be cultured and easily maintained in a small aquarium or deep pan filled with 2­3 inches of springwater (or aged tap water). At room temperature in the laboratory, populations double in about 3­4 weeks or less. Using a disposable plastic pipette, transfer a few dozen, undamaged, healthy worms into the aquarium. Never attempt to handle or transfer worms with forceps or hooks. They are easily injured by these instruments.

Next, add enough strips of brown paper towel to just cover the bottom of the container. The towel serves as a fibrous substrate of decomposing material, both for the worms and for numerous microscopic organisms that may cohabit the culture, such as bacteria, protozoans, rotifers, and ostracods.

Add sinking fish-food pellets as the primary food source for this simple aquatic ecosystem. Start by adding one or two pellets. After a few days, add one or two more, but only if the others have been consumed. Do not overfeed, since decomposition of uneaten food may contaminate the aquarium and cause a mass die-off of worms. Worms are not harmed, however, by irregular feeding or long periods of starvation.

Replace water lost to evaporation by adding springwater (or distilled water).I recommend continuous, gentle aeration, and this becomes increasingly important as biological decomposition of the paper occurs and as the worm population increases.

As the paper towel disintegrates and waste residues accumulate, replace the culture water regularly (about every two weeks) by slowly decanting it down a drain. Be careful not to lose remaining paper and worms at the bottom. After rinsing the paper and worms again with springwater, and decanting, refill the aquarium to the original level and add new pieces of towel. I suggest the occasional "harvesting" of surplus worms; these can be used for classroom experiments, as live food for fish, or for starting duplicate cultures. I strongly advise the maintenance of at least one duplicate culture. If you follow these procedures, the worms reproduce continuously by asexual reproduction (fragmentation), and cultures may be sustained for years.

Handling the worms is easy, but you should follow certain important precautions. Capture and handle the worms (or worm fragments) while they are immersed in water. Using an eyedropper or plastic disposable pipette, simply suck one or two up, along with a little water. Never pick up or handle the worms with forceps, hooks, or metal probes because even a slight injury by pinching or poking causes them to self-fragment (autotomize). However, if blackworms do become "dismembered," you need not discard the pieces­­just save them for further experiments.

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© Carolina Biological Supply Compagny, Article used by permission

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