|
Baban Ingole
(Corresponding
author)
|
National Institute of Oceanography (CSIR), Dona Paula,Goa
- 403 004, India
e-mail: baban@nio.org
|
|
Publication Data
Paper received:
24 October 2009
Revised
received:
26 February 2010
Accepted:
20 April 2010
|
Abstract
Life history of a
free-living meiobenthic nematode Daptonema normandicum
(DeMan, 1890) was studied in the laboratory. Live
specimens were primarily collected from the sewage outlet site near the mouth
of the Mandovi estuary, Goa. This species was the most dominant (>67%) among the meiobenthic nematodes. Vertically, nematode abundance was
highest at the surface sediment and correlated with the organic carbon and
sediment chlorophyll-a. Considering their dominance in the meiofauna, attempts were made to rear D. normandicum in laboratory. Salinity of the culture
medium was maintained at 14 to 17 PSU (same as the collection site). All the
culture experiments were conducted in semisolid nutrient agar media at 27 ?2oC
temperature for 12 hr dark: 12 hr light conditions. The food consists
primarily of an unidentified bacterium and mixed algae, but diatom and
ciliates were also observed in culture. Females produced first batch of eggs
at the age of 23 days. Gravid female normally carry 8-10 eggs. Embryonic
development is completed in ~72 hr and entire life cycle (egg to adult) was
completed in 22-24 days. Average size of juveniles at the hatching was 0.189
mm. Young individuals attains a maximum size of 1.23 mm (male) and 1.04 mm
(female) in? ~21-23 days. Growth, in
terms of length was augmented upto 23rd
day and ceased thereafter. The daily growth increment for the first 5 days
was 0.01-0.04 mm which increased upto 0.05-0.08 mm
d-1 during the maturation (10-18 days). Male :
female ratio was 1:2. In this laboratory study, we provided information on
the embryonic development, the life cycle and ecology. Our results demonstrated that D. normandicum
can be reared successfully under the controlled conditions, suggesting
possible use of this species in toxicological and aquaculture studies. The
culture method described is very handy and can be applicable for rearing
other meiobenthic species particularly the
nematodes with comparable feeding habits.
Key
words
Nematode, Daptonema normandicum,
Life history
|
|
Copyright ? 2011 Triveni Enterprises. All rights reserved. No part
of the Journal can be reproduced in any form without prior permission. Responsibility
regarding the authenticity of the data, and the acceptability of the
conclusions enforced or derived, rest completely with the author(s).
|
