1. PARENTAL CARE IN AMPHIEIA
In amphibians there are many devices for the protection
during the early stages of development and in this way
nature has practiced economy in the number of eggs,
which varies in direct proportion to the chances of
destruction.
These devices fall under two heads, which may be found
combined in some forms
firstly, protection by the parents, either by means of nest
or nurseries, or by direct nursing;
secondly, shortening of the metamorphosis. The different
modes of protection are given below in the three
important orders of class Amphibia
2. Protection by Means of Nests and Nurseries
A. In enclosures in the water: A large tree frog (Hyla
faber). lt protects its progeny by building a basin-shaped
nursery in shallow water on the border of the pond. The
female scoops mud to a depth of 3 or 4 inches and with
the material thus removed a circular wall is built which
emerges above the surface of the water.
3. The inside wall is smoothened by the webbed
and flattened hands; the bottom is leveled by
belly and hands. The eggs and early larvae are
thus protected from attack of many insects and
fishes, etc., at least for some time, heavy rains
later on destroy the wall and larvae go to the
water.
4. B. In holes near water:
A still better mode of protecting the offspring during the
early stages of development has been adopted by a
Japanese tree frog Rhacophorus schlegelii. The male and
female in embrace bury themselves in the damp earth on
the edge of ditch or fooded rice field, and make a hole or
chamber, a few inches above water level.
5. The walls of this chamber are polished and during this
process the gallery by which they enter into that
chamber gets obliterated, oviposition begins. The
female first produces a secretion from cloaca which is
beaten into a froth. The eggs are deposited into the
froth. Now the inactive male impregnates them, now
both of them separate and make an exit gallery towards
the ditch. It is obliquely downwards towards the water;
later on this is used by the lervae who come to the
water to complete the development.
6. The bubbles collapse, the froth liquefies and
this liquid acts as an efficient vehicle for
transporting. The larvae which are carried down
the tunnel into the water
7. In nests on trees or on rocks overhanging the
water:
Some tree frogs like Phyllomedusa in South
America, Rhacophorus malabaricus in India, and
Chiromantis in tropical Africa, deposit their
spawn on trees,
8. The froth is attached to one or many leaves
stuck together and overhanging a pool for a few
days. The larvae move in froth and after losing
the external gills, they fall in water to complete
metamorphosis.
9. In transparent gelatinous bag in the water: The
eggs of Phrynicabus biroi are large which are
enclosed in sausage-shaped transparent common
membrane secreted by the female and is left in
the mountain streams.
10. The whole development takes place within the
eggs and little frogs go out in perfect condition
NO gills have been observed and the large tail
serves as a breathing organ of young ones.
11. On trees or in moss away from water
In several species of tropical American genus
Hylodes, the eggs are deposited in damp places
under stones or moss or plant leaves and are of
large size.
12. The metamorphosis is hurried up within the egg,
there is a plenty of yolk in the egg and hence entire
development takes place there and young frog
hops out as an air breather with a vestige of tall
which was fully developed and highly vascularized
and served as a respiratory organ. No gills have
been seen.
13. Direct Nursing by the Parent
A. Tadpoles transported from one place to another
by males: Small South American frogs Phyllobates
and Dendrobates have been repeatedly observed
carrying well-developed tadpoles on their back.
14. Tadpoles adhere by their sucker-like lips and
flattened abdomen and thus they are carried from
one place to the other and in this way they can
even go from one pool to the other and this is
particularly when one pond is to dry
15. B. Eggs protected by male who covers with his body
The eggs of Mantophyrne robusta are strung together
by an elStic gelatinous envelope. They are seventeen
in number and form a lump over which the male sits,
holding it with both hands and development takes
place there. It may be outside water. The larvae have
no gilis, well developed legs, large tail which is
vascularand and respiratory.
16. Eggs carried by the parents
Midwife toads (Alytes) are a genus of frogs in
the family Alytidae and are found in most of
Europe and northwestern Africa.the males
carry a string of fertilised eggs on their back,
hence the name "midwife"
17. The female expels a strand of eggs, which the male
fertilizes externally. He then wraps them around his
legs to protect them from predators in the water.
When they are ready to hatch, the male wades into
shallow water, where he allows the tadpoles to leap
out of their eggs.
