3rd Year Special Annual Double Issue Vol 4 Issue 1 & 2 Jan - Apr 2 3rd Year Special Annual Double Issue Vol 4 Issue | Page 116

ADVENTURE & WILDLIFE
They are used as food by humans in
various cultures worldwide, and are raised on
farms in some areas for use as food.
Freshwater Snail
Freshwater snails are gastropod mollusks which
live in freshwater. There are many different
families. They are found throughout the world in
various habitats, ranging from ephemeral pools
to the largest lakes, and from small seeps and
springs to major rivers. The great majority of
freshwater gastropods have a shell, with very
few exceptions. Some groups of snails that live
in freshwater respire using gills, whereas other
groups need to reach the surface to breathe air.
In addition, some are amphibious and have both
gills and a lung (e.g. Ampullariidae). Most feed on
algae, but many are detritivors and some are filter
feeders.
According to a 2008 review of the taxonomy,
there are about 4,000 species of freshwater
gastropods (3,795-3,972).
At least 33–38 independent lineages of
gastropods
have
successfully
colonized
freshwater environments. It is not possible to
quantify the exact number of these lineages
yet, because they have yet to be clarified within
the Cerithioidea.From six to eight of these
independent lineages occur in North America.
Sea Snail
Sea snail is a common name for snails that
normally live in salt water, in other words marine
gastropods. The taxonomic class Gastropoda
also includes snails that live in other habitats,
such as land snails
and freshwater snails. Many species of sea snails
are edible and exploited as food sources by
humans.
Slugs
Gastropods
that
lack
a
conspicuous
shell
are
commonly
called slugs
rather
than
snails. Some
species
of
slug have a red
shell, some
have only
an internal
116
vestige that serves mainly as a calcium
repository, and others have no shell at all. Other
than that there is little morphological difference
between slugs and snails. There are however
important
differences
in
habitats
and
behavior.
A shell-less animal is much more maneuverable
and compressible, so even quite large land
slugs can take advantage of habitats or retreats
with very little space, retreats that would be
inaccessible to a similar-sized snail. Slugs
squeeze themselves into confined spaces
such as under loose bark on trees or under
stone slabs, logs or wooden boards lying
on the ground. In such retreats they are
in less danger from either predators or
desiccation, and often those also are suitable
places for laying their eggs. Slugs as a group
are
far
from
monophyletic;
biologically
speaking ‘slug’ is a term of convenience with
little taxonomic significance. The reduction or loss
of the shell has evolved many times independently
within several very different lineages of
gastropods. The various taxa of land and sea
gastropods with slug morphology occur within
numerous higher taxonomic groups of shelled
species; such independent slug taxa are not in
general closely related to one another.
In Agriculture
There are a variety of snail-control measures
that gardeners and farmers use in an attempt to
reduce damage to valuable plants. Traditional
pesticides are still used, as are many less
toxic control options such as concentrated
garlic or wormwood solutions. Copper metal is
also a snail repellent, and thus a copper band
around the trunk of a tree will prevent snails from
climbing up and reaching the foliage and fruit.
Placing crushed egg shells on the soil around
garden plants can also deter snails from coming
to the plants.The decollate snail (Rumina
decollata) will capture and eat garden
snails,
and
because
of
this
it
has
sometimes
been
introduced
as
a
biological
pest control
Vol 4 | Issue 2 |Mar - Apr 2019