OBSERVATIONS ON COHORTS OF TUBIFEX-TUBIFEX CULTURED AT DIFFERENT FOODLEVELS, USING CELLULOSE SUBSTRATE

In order to clarify the relationship between food availability and pop ulation dynamics in aquatic oligochaetes, short term cultures and coho rt cultures of Tubifex tubifex were reared using substrates with diffe rent food concentrations, obtained by mixing sand with different amoun ts of cellulose powder. In short term experiments, T. tubifex seemed c apable of utilizing cellulose substrates for growth or egg production. Yet, in the cohort experiment, newly hatched worms could not grow on cellulose substrates. Survivorship, however, appears to be influenced by cellulose concentration giving an indication that this material, al though inadequate, is somehow utilized.