Parental Care in Amphibians
Parental care can be defined as the activities which are directed by an animal towards the protection and maintenance of its own offspring or those of a near relative.
In comparison to birds and mammals, little parental care is found 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.
Among amphibians, parental care includes attendance of the eggs, transportation of eggs or larva, and feeding of larvae.
Parental care is associated with only those species that place their eggs in single clusters, never with those that scatter their eggs in aquatic situations.
Nest construction, either prior to or during opposition, is not considered to be parental care, although in some species that construct nests one parent may attend to the eggs. Likewise, the retention of eggs in the oviducts, even though nourishment is provided to the developing young, is not considered to be parental care
Different types of Parental Care in amphibians:
Various processes are found in amphibians for parental care:
1. Selection of site: some amphibians lay their eggs on safe and moist land, very near to water.
- Rhacophorus schlegli of Japan lays eggs in a hole on the muddy bank of a river or pond with foamy mucus cover to prevent the eggs from drying.
- In Gyrinophilus the eggs are laid under the stones in a stream. Sometimes, the eggs are taken up by the body.
- In Hylodes, the eggs are laid on the undersurface of leaves hanging above the water.
- In triton, the eggs may be fixed with the aquatic weeds by glues.
2. Frothing of water:
- In Rhacophorus maculates, after the eggs are laid, the surrounding water is made frothy by the limb movement, which prevents the eggs from desiccation and escaping from the eyes of the predators.
3. Defending Eggs:
- Males of green frog Rana clamitans defend their eggs by not allowing small-sized intruders in their territories.
- Males of Mantophryne robusta hold with their hands a cluster of eggs in a gelatinous envelope.
4. Formation of Nests: Some amphibians build nests for the deposition of eggs.
- Mud nest– Hyla faber digs small holes in the mud for deposition and development of eggs.
- Leaf Nest – In a South American tree frog Phyllomedusa hypochondrales, the margin of the leaves are folded and glued together which acts as a nest for the eggs.
- Shoot Nest – Triton constructs the nest by fixing the shoots with a gelatinous secretion.
5. Direct development: Some terrestrial or tree frogs, like hylodes and Hyla nebulosi, the eggs hatch directly into tiny juveniles avoiding predator attach and larval mortality.
6. Carrying eggs over the body
- Coiling around eggs:
- Amphiuma, Ichthyphis females after laying eggs guard them by coiling the body till the egg hatch.
- In Megalobranchus, the males perform the same function.
- Transferring tadpole to water: Phylobates,, Pelobates species inhabiting tropical Africa and South America hold the newly hatched tadpoles with their mouth and transport them to water.
- Eggs glued to the body:
- In Salamander desmognathus fuscus females carry clusters of eggs glued to their bodies.
- In Sri Lankan tree frogs, Rhacophorus reticulates, the eggs are glued to the belly of the females.
- In a European frog, Alytes obstetricians, instead of the female’s parental care, the male entangles the eggs around his hind legs.
- Eggs in back pouches:
- In Hyla geoldii, the females carry the eggs on their backs.
- In Desmognathus, the females carry the eggs and live in an 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 eggs.
- In Pipa dorsigera, the eggs are developed in pits on the back of the females. Embryonic development occurs within the pits and physiological exchange takes place between the females and the larva.
7. Organs as brooding pouches:
- South American male frog 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.
8. Viviparity: It is a special type of reproductive behavior 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.
You can also read:
- General Characters of Uromastyx
- Characteristics and Classification of Phylum- Chordata
- Scoliodon – Dogfish, Classification, and Characteristics
- Subphylum – Urochordata
- Herdmania- Sea Squirts
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