Regeneration ability in seventeen top soil and sub soil earthworm species

Abstract

Aim The present study was carried out to record the regeneration ability in the top soil earthworm species inhabiting 0-15 cm soils with unpredictable environment and exposed to predator pressure and the sub soil species living below 15 cm soil depth where environment was stable with less exposure to predators. Methodology Out of a total of 17 laboratory acclimatized earthworm species, 12 top soil and 5 sub soil species were subjected to amputation of either anterior (5) or posterior (5) body segments or both by sterilized blade. Amputed earthworms in separate experimental groups were kept in decomposed cow dung (epigeic species) and habitat soils (for others) under laboratory conditions (temperature 26°C ± 0.22, RH 70-90%). Results In contrast to the sub soil earthworm species, the top soil species in generaly had the ability of regeneration of body segments. Top soil species viz., Perionyx excavatus, Eisenia fetida, Eudrilus eugeniae, Octochaetona beatrix, Lampito mauritii, Giyphidriius sp., Dichogaster sp., Drawida papiiiifer papiilifer, Drawida assamensis, Pontoscoiex corethrurus and Polypheretima elongata had the regeneration ability and of them only former seven species amputed segments, while rest of the species regenerated only the posterior segments. Interpretation In contrast to the sub soil earthworm species viz., Eutyphoeus gammiei, E. comillahnus, Metaphire houlleti, Amynthus alexandri and Kanchuria sp., the top soil species in general were subjected to predator attacks and agricultural practices (ploughing) leading to loss of segments, and thus were equipped with the powerof regeneration.