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Abstract
Aim:
The aim of the present study was to observe the role of cerebral ganglionic
neurosecretory cells (NSCs) during cocoon production in native earthworm
species Perionyx ceylanensis subjected to amputation and seasonal
variations.
Methodology: Histological studies (using Aldehyde Fuchsin and
Chrome Alum Haematoxylin Phloxin stain) were carried out on brain NSCs in the
two groups of earthworms (Group I and Group II) maintained in earthen culture
pots (2L) with cowdung as food. Group I comprised of brain amputed earthworms
was subjected to observe the role of brain NSCs in production of cocoon and
Group II earthworms subjected to seasonal changes in the cerebral NSCs during
cocoon production. Five replications were kept for Group I (1 individual per
pot) and Group II (1 pair per pot).
Results:
Group I debrained earthworms started to lay cocoons from the 31st
day following regeneration of cerebral ganglionic type A NSCs. In group II
worms the highest neurosecretory activity was registered in the cerebral type
A cells, especially during monsoon coinciding with the hike of cocoon
generation.
Interpretation: Appearance of type A NSCs in regenerated
brain and peak of type A neurosecretory cell activity during peak
reproductive period of earthworm species (as indicated by peak of cocoon
production) indicates the possible role of cerebral type A NSCs in cocoon
laying.
Key
words:
Amputation, Cocoon production, Neuroendocrine system, Neurosecretory cells, Perionyx
ceylanensis
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