Cocoon production,morphology, hatching pattern and fecundity in seven tropical earthworm species — a laboratory-based investigation

Data on the reproductive biology of seven Indian species of earthworms, viz.Perionyx excavatus Perrier,Lampito mauritii Kinberg,Polypheretima elongata (Perrier),Pontoscolex corethrurus (Muller),Eutyphoeus gammiei (Beddard),Dichogaster modiglianii (Rosa) andDrawida nepalensis Michaelsen are presented. The peregrine earthworms such asPerionyx excavatus, Pontoscolex corethrurus, Dichogaster modiglianii, andPolypheretima elongata are considered to be continuous breeders with high fecundity. NativeLampito mauritii andDrawida nepalensis are semi-continuous andEutyphoeus gammiei discrete breeders. There is a dramatic increase in cocoon production by most earthworm species of Tripura in the summer and monsoon with a corresponding peak during April and July. Cocoon production decreased or ceased during winter. Temperature affected the incubation period of cocoons. With increase in temperature, incubation period increased in the endogeic worms,Pontoscolex corethrurus, Polypheretima elongata andDrawida nepalensis and decreased in the epigeic worms,Perionyx excavatus andDichogaster modiglianii, within a temperature range between 28–32°C under laboratory conditions. There was a significant(P < 0.05) positive correlation between number of hatchlings per cocoon and incubation period inLampito mauritii. High rate of cocoon production, short development time with high hatching success, as well as continuous breeding strategies in the epigeic speciesPerionyx excavatus andDichogaster modiglianii and the top soil endogeic species,Pontoscolex corethrurus,Drawida nepalensis andLampito mauritii, indicate their possible usefulness in vermiculture. The giant anecic worm,Eutyphoeus gammiei, which has a very long cocoon development time, discrete breeding strategy and very low rate of cocoon production, is not a suitable species for vermiculture.     

Earthworm Communities in the Bamboo Plantations of West Tripura (India)

Present study revealed the presence of 16 earthworm species belonging to 11 genera and four families viz. Megascolecidae (Amynthus alexandri, Metaphire houlleti, Lampito mauritii, Kanchuria sp1, Perionyx excavatus), Octochaetidae (Eutyphoeus gigas, Eutyphoeus comillahnus, Eutyphoeus orientalis, Octochaetona beatrix, Dichogaster bolaui, Lennogaster chittagongensis, Lennogaster yeicus), Moniligastridae (Drawida papillifer papillifer, Drawida assamensis, Drawida nepalensis) and Glossoscolecidae (Pontoscolex corethrurus) in the soils of five bamboo species [Bambusa balcooa (Sil Barak), Melocanna baccifera (Muli), Bambusa polumorpha (Bari), Bambus cacharensis (Bom) and Bambus bambus (Katabarak)] of West-Tripura. While four earthworm species viz. Metaphire houlleti, Drawida assamensis, Drawida papillifer papillifer and Pontoscolex corethrurus were common to all species of bamboo plantations, the rest showed restricted distribution. Among the earthworm species 4 were exotic (Amynthus alexandri, Metaphire houlleti, Dichogaster bolaui and Pontoscolex corethrurus) and the others were native to the Indian sub-continent. In general, earthworms under the bamboo plantations occurred within temperature range of 21.6 °C–28.0 °C, pH 4.0–7.0, organic matter 0.56–5.99 %, moisture 9.6–31.7 %, water holding capacity 14.6–43.9 % and bulk density 0.7–1.8 g cm^?3. The average density and biomass of the earthworms in the studied places were 108 ind m^?2 and 44 g m^?2 respectively. Earthworm diversity, dominance and evenness indices showed the values 1.00, 0.47 and 0.70 respectively. Earthworm density and biomass showed a negative correlation with temperature whereas those had a strong positive correlation with pH, moisture and organic matter of the soils.