444
N. BALARRISHNAN NAIR AND M. SARASWATHY
artificial sea water without any additional food but was not successful
with Teredo navalis since they failed to breed, probably on account of
the inadequate nutrition, owing to the absence of any protein-rich
plankton. It is probable, as Turner (1966) has suggested, that “ the
adults of some species may require planktonic food at least during the
breeding period and some may be capable of surviving on plankton
only as do many other bivalves ”. Probably this is true of Kuphws,
Teredora and Uperotus. Plankton with its rich nitrogen content must
be essential for the normal growth of shipworms. This conclusion has
been confirmed by the recent experiments of Karande et al. (1968) on
Teredo furcifera which were maintained in aquaria from initial settlement ; they grew and propagated only if they were provided with nanoplankton through a system of running sea water. These authors maintained these borers in laboratory tanks over a period of 2 years raising
0
0
0 leucine
0
phenylalanine
0
0 valine
0
0 tyrosine
0
0 proline
0
0
rnethionine
0
0
alanine
0
0
arginine
Teredo Wood Nanoplankton
FIG. 47. Amino acid composition of adult Teredo, of the wood in which it lives and of
nanoplankton collected from local s m water. (After Lane, 1955).
five generations under controlled conditions. These observations are
significant since wood has been shown to be deficient in the aromatic
amino acids phenylalanine and tyrosine, in the heterocyclic amino acid
proline, and in valine, all of which are present in shipworms. Hydrolysates of nanoplankton contain all of these missing amino acids except
phenylalanine (Fig. 47).
There is also the factor of overcrowding which turns the timber into
a porous and highly fragile mass permitting entry of parasitic Protozoa
and harmful bacteria-a serious menace to the life of the community
as found by Grave (1928). Probably it is under these conditions that
shipworms perish owing to the depletion of the substrate and not because of starvation. The observation of Lane (1955), that “population
N. BALARRISHNAN NAIR AND M. SARASWATHY
artificial sea water without any additional food but was not successful
with Teredo navalis since they failed to breed, probably on account of
the inadequate nutrition, owing to the absence of any protein-rich
plankton. It is probable, as Turner (1966) has suggested, that “ the
adults of some species may require planktonic food at least during the
breeding period and some may be capable of surviving on plankton
only as do many other bivalves ”. Probably this is true of Kuphws,
Teredora and Uperotus. Plankton with its rich nitrogen content must
be essential for the normal growth of shipworms. This conclusion has
been confirmed by the recent experiments of Karande et al. (1968) on
Teredo furcifera which were maintained in aquaria from initial settlement ; they grew and propagated only if they were provided with nanoplankton through a system of running sea water. These authors maintained these borers in laboratory tanks over a period of 2 years raising
0
0
0 leucine
0
phenylalanine
0
0 valine
0
0 tyrosine
0
0 proline
0
0
rnethionine
0
0
alanine
0
0
arginine
Teredo Wood Nanoplankton
FIG. 47. Amino acid composition of adult Teredo, of the wood in which it lives and of
nanoplankton collected from local s m water. (After Lane, 1955).
five generations under controlled conditions. These observations are
significant since wood has been shown to be deficient in the aromatic
amino acids phenylalanine and tyrosine, in the heterocyclic amino acid
proline, and in valine, all of which are present in shipworms. Hydrolysates of nanoplankton contain all of these missing amino acids except
phenylalanine (Fig. 47).
There is also the factor of overcrowding which turns the timber into
a porous and highly fragile mass permitting entry of parasitic Protozoa
and harmful bacteria-a serious menace to the life of the community
as found by Grave (1928). Probably it is under these conditions that
shipworms perish owing to the depletion of the substrate and not because of starvation. The observation of Lane (1955), that “population