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) and Drawida nepalensis Michaelsen are presented. The peregrine earthworms such as Perionyx excavatus, Pontoscolex corethrurus, Dichogaster modiglianii, and Polypheretima elongata are considered to be continuous breeders with high fecundity. Native Lampito mauritii and Drawida nepalensis are semi-continuous and Eutyphoeus 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 and Drawida nepalensis and decreased in the epigeic worms, Perionyx excavatus and Dichogaster modiglianii, within a temperature range between 28-32 degrees C under laboratory conditions. There was a significant (P < 0.05) positive correlation between number of hatchlings per cocoon and incubation period in Lampito mauritii. High rate of cocoon production, short development time with high hatching success, as well as continuous breeding strategies in the epigeic species Perionyx excavatus and Dichogaster modiglianii and the top soil endogeic species, Pontoscolex corethrurus, Drawida nepalensis and Lampito 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.
Purpose Rubber leaves are the abundant agro-waste and pineapple, the most economically important fruit crop in Tripura. So, in our present study, different amounts of rubber leaf vermicompost have been applied to the soils of pineapple plantation to determine their effects on earthworms-the soil ecosystem engineers, coupled with the vegetative growth and yield of pineapples. Methods During 30 months of field trial (2010-2012) in ICAR regional station, Lembucherra, West Tripura, the control plot (T 0 ) received no fertilizer, while experimental plots were fertilized with four different amounts of vermicompost viz. T 1 (5 tons ha -1 year -1 ), T 2 (10 tons ha -1 year -1 ), T 3 (20 tons ha -1 year -1 ) and T 4 (30 tons ha -1 year -1 ). Results A significant (p \ 0.05) but gradual increase in density (up to T 3 treatment) and biomass (up to T 4 treatment) of earthworms were recorded with the increasing amounts of vermicompost. During the second year, average length and width of leaves, number of leaves per plant, plant girth, fruit weight, fruit yield and fruiting percentage were highest in the T 3 plot compared to other treated plots and control.
ConclusionThe present study reveals that crop yield is very much related to the particular concentration of vermicompost, beyond the level of which production declines and increase in vegetative growth, fruit weight and fruiting percentage of pineapple are strongly linked with the soil pH, av. P, av. K, clay content and the earthworm density of soils.
Transection of anterior 5 segments in Metaphire peguana engenders characteristic changes in the functional activity of the ventral nerve cord-neurosecretory system in the event of cephalic regeneration. Of the two types of neurosecretory cells, the moderately stained cells remain more susceptible when the cell structure, location of nucleus, amount of secretory inclusions and their transportation to the zone of accumulation are considered. Overall engorgement of neurosecretory substances refrained from axonal transport, moderate axonal flow coupled with slight depletion and finally acute depletion at 24, 48 and 72 hr after amputation respectively are some of the notable features registered in course of this investigation. Disarray in the sequential changes involved in the secretory dynamics of neurosecretory cells, as well as extent of NSM accumulation both within and outer periphery of the ganglia. provide evidence for the utilisation of material through repaired vascular systems during regenerative proliferations of anterior segments.
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