DETERMINATION OF THE ORIGIN OF THE DIFFERENT GROWING ABILITIES OF 2 POPULATIONS OF MILLSONIA-ANOMALA (OMODEO AND VAILLAUD), A TROPICAL GEOPHAGEOUS EARTHWORM

Individuals of the tropical endogeic earthworm Millsonia anomala from population of savannah patches cannot grow when introduced in a forest soil while forest individuals can grow in both soil types. Laboratory cultures in both soil types were performed to explain the differences observed. The quality of the soil organic matter or the available mic roorganisms present in the soil may be responsable of worms growth. Th e most likely hypothesis was that the ability to digest soil organic m atter may be aquiered during the early stages of life when the gut is first colonized by particular soil microbial populations and that thes e microorganisms stay in the gut during the rest of the life-span.