A topic of chordate.

1. PARENTAL CARE IN AMPHIBIA
-By Sampriya Ghosh

2. DEFINITION:-
Looking after the eggs or the youngs untill they are
independent to defend themselves from predators is known
as PARENTAL CARE.
 By comparison with birds and mammals,
amphibians generally have been thought to exhibit
little parental care.
 However, in recent years both field and laboratory
studies have provided evidence for an astonishing
array of parental care in amphibians. Parental care
may be defined as any behavior exhibited by a
parent toward its offspring that Increases the
offspring’s chances of survival (Trivers. 1972).
 Anurans show greater diversity than Urodales or
Apodans.

3. Parental is divided in to two
broad catagories:-
1. PROTECTION BY NESTS,NURSERIES OR
SHELTERS.
2. DIRECT CARING BY PARENTS.

4. 1. PROTECTION BY NESTS,NURSERIES OR
SHELTERS:-
 SELECTION OF SITE :-
1. Some amphibians lay their eggs in safe and moist land, very near
to water.
2. Rhacophorus schlegli of Japan, lays eggs in a hole on muddy
bank of river or pond with foamy mucus cover to prevent the eggs
from drying.
3. In Gyrinophilus the eggs are laid under the stones in stream.
Sometimes, the eggs are taken up on the body.
4. In case of Hylodes, eggs are laid on the under surface of leaves
hanging above water.
5. In Triton the eggs may be fixed with the aquatic weeds by glues.

5. 2. FROTHING OF WATER:-
Some Anurans just after laying eggs, surrounding water is made
frothy by wringgling movements of the hind limbs, so that the
eggs are prevented from desiccation and can escape the site of
enemies.
3. FOAM NEST:-
Rachophorus maculatus secretes a jelly like secretion with eggs
from time to time which is beaten by the cross wise movement of
the hind limbs of the female partner only resulting in formation of
frothy mass. First this frothy mass looks white but gradually truns
yellowish. This mass with eggs called FOAM NEST. With in few
hours this mass the outer surface hardens gradually.

7. 4. Formation of Nests:
Some amphibians build nests for deposition of eggs.
1.Mud Nest:
Brazilian Hyla fabre digs small holes in the mud for
deposition and development of the eggs.

8. 2.Leaf Nest:
In a South American tree frog Phyllomedusa hypochondrales, margin of the
leaves are folded and glued(cloacal secretion) together which acts as nest for
the eggs.

9. 3.Shoot Nest:
Triton construct the nest by fixing the shoots with a gelatinous secretion.
4.Gelatinous bags :-
In Phrynixalus biroi large eggs are enclosed in sausage shaped transparent
gelatinous membranous bags.
5.Communal nest:-
The toad Nectophyrinoids malcolmi prepare communal nests in which the eggs are
deposited by several females.
This nest is guarded by a single male.

10. DIRECT CARING BY PARENTS
i) Coiling around eggs:
Ø Amphuima, Ichthyphis females after laying eggs guard them by
coiling body till the eggs hatch.
Ø In Japaneese salamander Megalobatrachus maximus, the
males perform the same function.

12. ii) Transferring tadpoles to water:
 Phylobates, Pelobates(both are terrestrial) species inhabiting
tropical Africa and South America hold the newly hatched tadpoles
with their mouth and transport them from land to water.
 Anthroleptis males carries the tadpoles from one pond to another.

14. iv) Eggs glued to the body:
 Salamander Desmognathus fuscus females carry cluster of eggs
glued to their body.
 In Sri Lankan tree frog, Rhacophorus reticulates, the eggs are
glued to the belly of the females.
 In a European frog, Alytes obstericans, instead of female’s
parental care, the male entangles the eggs around his hind legs.

16. iv) Eggs in back pouches:-
 In Hyla goeldii, the females carry the eggs on their back.
 In Desmognathus, the females carry the eggs and live in
underground hole.
 In Pipa pipa, the eggs are carried by females on the back.
 In Cryptobatrachus evansi the dorsal skin contains many small
pockets for lodging of eggs.
 In Pipa dorsigera, the eggs are developed in the pits on the back
of the females. During breeding season, the dorsal skin becomes
soft, spongy, and vascular. Embryonic development occurs within
the pits and physiological exchanges takes place between the
females and the larva.

19. v) Organs as brooding pouches:-
 South American male frog of Rhinoderma darwinii keeps fertilized eggs in his
vocal sacs where they undergo complete development.
 In Hylambates breviceps, the female carries eggs in her buccal cavity.
 Australian frog Rheobatrachus the female keeps the egg in her stomach,
tadpoles expelled through mouth after metamorphosis.

21. vi) Viviparity:
A special type of reproductive behavior is observed in Salamandra atra and S.
maculosa. The eggs are placed inside the uterine cavity where the entire
development takes place. The uterine wall functions physiologically as primitive
placenta.