Amphibians exhibit two main types of parental care: protection of eggs/young through nests/shelters, and direct caring behaviors. For protection, many frogs lay eggs near water in moist habitats and defend the eggs or territories. Some frogs have direct development where eggs hatch into small frogs. Others make foam, mud, or gelatinous nests. For direct care, some species coil around eggs, transport tadpoles to water, glue eggs to their bodies, carry eggs on their backs, or use vocal sacs or viviparity to brood eggs. Parental care helps offspring develop and avoid predators until independence.
2. Amphibia
Amphibians are vertebrate tetrapods .Amphibians include frog salamanders
and caecillians.
The term amphibians loosely transelate from the greek as “dual life”
which is a refrence to the metamorphosis that many frogs and salamander
undergoes and their mixture of aquatic and terrestrial environments in their
life cycle .
Amphibian evolved during the Devonian period where the earliest
terrestrial tetrapods.
3. Parental care in amphibia.
Looking after the eggs or the young ones untill they are
independent to defend from predators is known as parental
care.
The methods of carrying by amphibia generally fall under two
broad categories:-
1. Protection by nest ,nurseries ,or shelters.
2. Direct carying by parents.
4. Protection by nest ,nurseries, or shelters
1. Selection of sites:-Many amphibians lay eggs in moist micro
habitat on land .Many tropical frog and toads lay eggs on land
near water .Many tree frog lays egg not on land but on leaves
and branches overhanging water.
eg: species of phyllomedusa and rhacophorus etc.
1. Defending eggs or territories:- Males of green frog Rana
clamitans and others species maintains territories and attack
small intruder to defend egg.Male or female even both guard
the eggs.
5. 3. Direct Development:-In some terrestorial or tree frogs such
as arthroliptis, hylodes, hylamedulosa, the egg hatch directly
into little frog, thus avoiding larval mortality.
4. Foam nest:- Many amphibians convert copious mucous
secretion in to the nest for their young. Japaneese tree frog
Rhacophorus schlegalli , the mating couple digs hole or tunnel
into which eggs are left into the froathy mass to avoid
dessication.
6. 5. Mud nest:- In brazillian tree frog hyla fabe ,the male digs a
hole or nursery in mud in shallow water ,in which the female
lays her eggs.
6. Gelatinous Bags:- In phyrinixalus biroi large eggs are
enclosed in a sausage –shaped transparent gelatinous
membrane bag , secreted by female and left in mountains
streams.
7.
8. Direct caring by Parents.
1. Coiling around eggs:- In congo eel ,Amphiuma and certain
caecillians the female lays large egg in burrow in damp soil and
carefully guards then by coiling her body around them untill hatch.
2. Transfering tadpole to water:- Some species of small frogs in both
tropical Africa and S. America ,the hatching tadpole fasten
themselves to the back of one of the parents with their sucker like
mouth and transported to water.
3. Egg glued to body:-Many amphibians instead of remaining with
the eggs ,carry egg glued to their body .In the dusky salamander
the female carry string of eggcoiled around the neck untill they
hatched.
9. 4. Eggs on her back pouches:- In one group of tree frog called
marsupial frog or toad .inwhich the female carry the egg on
her back either in open oval depression and or individual
pocket.
5. Organs as brooding pouches :-Male of the terrestorial South
American frog Rhinoderma darwinii pushes atleast two
fertilised egg into his relatively large vocal sacs .They undergo
complete development to emerge out as fully formed froglets .
6. Viviparity:- Some anurans and oviviviparous .They retain
their egg in oviduct and the female give birth to young ones.
Eg.Nectophyrenoids.