EFFECT OF EARTHWORM DENSITY ON THE GROWTH AND REPRODUCTION OF LUMBRICUS-TERRESTRIS L (OLIGOCHAETA, LUMBRICIDAE) IN CULTURE

Experiments examining growth and reproduction of Lumbricus terrestris, by varying earthworm density at 20-degrees-C, in laboratory culture, are described. Densities up to 62 g live mass litre-1 were attained du ring growth experiments in 0.3 litre pots, but sexual maturity of the earthworms was not attained above 53 g live mass litre-1. From the hat chling stage minimum time to maturation was twelve weeks reaching a fi nal density of 15 g live mass litre-1. Greatest reproductive output at 4.4 cocoons worm-1 month-1 was recorded at a density of 15 g live mas s litre-1 in 0.75 litre pots with a depth of 0.076 m. Cocoon productio n occurred in 0.6 litre pots but high mortality was recorded above 19 g live mass litre-1. Overall the results suggest that in a large produ ction system soil depth could be kept to a minimum but population dens ities ought to be maintained towards the lower end of the range 15 - 2 5 g live mass litre-1.