194 Phylum Annelida 



Family tubificidae 



TUBIFICIDAE 



George R. La Rue, University of Michigan 



OLIGOCHAETE worms of the family Tubificidae form an excellent 

 food for many kinds of laboratory animals including planaria, 

 leeches, dragonfly and damselfly nymphs, aquatic beetle larvae, and 

 many fishes. A star-nosed mole kept in the laboratory ate them vora- 

 ciously. The ease with which these worms may be collected in quantity 

 and kept for months in the laboratory, and the avidity with which 

 they are eaten, make them important laboratory animals. 



Tubificidae occur in a considerable variety of freshwater habitats. 

 They may be found most readily and most abundantly in the mud, or in 

 muddy borders, of streams or ponds where considerable organic matter is 

 undergoing decay. When in shallow water they may often be seen with 

 their tails waving in the water, their heads buried in the mud. The 

 location of tubificids in soft muddy borders of streams or ponds may 

 often be determined by noting numerous small casts on the surface. 

 When their presence is suspected take up a small quantity of mud on a 

 trowel and examine it for worms. If they are abundant determine how 

 deeply they are embedded in the mud, then scrape or scoop up the layer 

 of mud containing them with trowels or small shovels and put in 10- or 

 12-quart pails. 



At the laboratory put the contents of a 12-quart pail in a shallow gal- 

 vanized pan measuring about 15 x 12 x 3 inches deep. Set the pan on 

 a drain table in a cool room and allow a very small stream of water from 

 a faucet to flow continuously through a rubber tube into the pan. The 

 worms will come to the surface in a few hours. During the night small 

 masses of worms tend to migrate out of the pan and onto the drain table 

 if the pan is overcrowded. These may be used for feeding purposes until 

 the stock is reduced. 



If the mud rises in the pan because of the formation of gas, prick holes 

 in it and press it down. 



In quiet rivers receiving sewage or in ponds to which manure has 

 been added to increase productivity of fish food, tubificids often collect 

 in masses as large as a man's fist, or larger, at the surface, either on or 

 near the decaying material and frequently near the margin or even upon 

 the muddy border. They occur when the water is warm and disappear 

 when it gets cold in the fall. Such worm masses are collected with a large 

 tea strainer, dipper, or long-handled fine-meshed dip net. In the labora- 

 tory they may be put with mud and decaying vegetable matter, or with 

 manure, potato, or other food material free from mud. 



