The primary minerals anorthite, biotite and olivine (obtained commercially, ground and sieved to 63 – 250 micron) and the secondary minerals kaolinite, illite and smectite, together with ground manure were used to make artificial soils in which earthworms which occupy three contrasting ecological niches - Eisenia veneta (lives in the litter layer), Allolobophora chlorotica (lives in mineral-rich soil) and Lumbricus terrestris (lives in semi-permanentvertical burrows) – were cultivated2,3.