Zoo CC305 Parental Care in Amphibians.pdf
- 1. Semester-III ZOO CC305 Self learning PARENTAL CARE IN AMPHIBIANS Dr. Sister M. Stuti A.C Assistant Professor Department of Zoology Patna Women’s College
- 2. OBJECTIVES At the end of the lesson, the students will be able to : • define Parental Care • explain parental Care in Amphibians • list the different modes of Parental Care in amphibians • elucidate how they protect their eggs and young ones • give examples and draw different diagrams of amphibia • list the advantages of Parental Care in amphibia
- 3. • Introduction • Methods • Examples • References
- 4. INTRODUCTION •Parental care can be defined as any non-genetic contribution by a parent that increases the fitness of offspring and can occur before or after laying or birth.(Stahlschmidt & DeNardo,2011) •Parental care in Amphibia may be defined as any behaviour exhibited by a parent towards its offspring’s chances of survival (Trivers,(1972)
- 5. INTRODUCTION •Looking after the eggs or young until they are independent to defend themselves from predators is known as parental care •Parental care is very important factor for survival •Parental care behaviour is any behaviour performed after breeding by one or both parents, that contributes to the survival of their offspring. Parental care is a form of altruism (unselfish concern for other) in spending time and energy to aid its offspring. The degree of parental care varies considerably, from species to species and depends upon the number of offspring produced.
- 6. •The amphibians were the first among vertebrates to invade land. They faced the most hardship and were anxious about the continuation of their race. Hence they developed various ways and means to protect their progenies. The methods of caring by amphibians is mainly divided into two categories A) Protection by nests and nurseries B) Direct carring by parents •The continuation of race is made possible by rearing of the offspring. Male and female giving food, shelter and protection to their off springs is parental behaviour.
- 7. A.Protection by means of nest and nurseries. Deposition of eggs in suitable places: In Triton the eggs may be fixed with the aquatic weeds by glues. A number of different species of frogs lay their eggs in suitable place either in water or outside the water. In water- Rana tigrina (Indian Frog) lay eggs in pond water in a jelly like bunch.
- 8. On tree or away from water American frog Hylodes keep their eggs below the rocks, mosses and on leaves of trees. The eggs of these species are larger and development takes place fast as yolk is in sufficient quantity
- 9. Construction of Nest A number of different species of frogs construct nests or shelters in which the eggs are laid. They construct following different types of nests. MUD NEST-Female tree frog Hyla faber Form nurseries at the bottom of the shallow pond for care of eggs .They construct 7-10cm deep hole in the mud in shallow water. Mud nests
- 10. Females lays eggs in nests and male discharge sperms to fertilize eggs. Tunnel nest Female Japanese tree frog (Rhacophorus Ocellatus) makes a spherical hole in mud at pond banks and lays eggs and males discharge sperm and fertilize the eggs
- 11. Construction of Nest Leaf Nest Tree frog of South America (Phyllomedusa malabariens) ,Africa (Chiromatis) lts eggs on rolled up leaves hanging above water.The nest is covered by many leaves.Eggs develop into tadpoles.The tadpoles directly fall into the water.Further metamorphosis of larva take place in water.After two to three weeks tadpoles fall into water.
- 12. • Female grass frog of rain forest Costa rica lay her eggs on leaves of tree and males take care of eggs.
- 13. Foam nests Many amphibians convert copious mucous secretion into nests for their young. In Japan tree frog Rhachophros schlegeli, the couple dig a hole into which eggs are left in a frothy mass to avoid desiccation. During rains hatching tadpoles are washed down the slopping tunnels into ponds or rivers water for further development. Floating form nest
- 14. . • The female of South American tree frog, Leptodactylus mystacinus,stirs up a frothy mass of mucus, fills it in holes near water and lays eggs in them. • Male frog Adelotus brevis lays eggs in foam nests.
- 15. Gelatinous bags: Female Phyrynixallus biroi secrets a transparent bag and keep their fertilized eggs in it.The transparent membranous bag is left in water current of hill stream.Entire metamorphosis occurs in it ,small frog come out of this bag after maturation. Communal nests: The toad Nectophyrynoides malcolmi prepare communal nests in which eggs are deposited by several females.This nest is guarded by a single male.
- 16. B-Direct caring by parents Carrying of eggs over the body Eggs are protected by covering them with their body- Male Mantophryne robusta species covers the eggs by elastic gelatanious covering in row.Male sits on the eggs and hold them with forelimbs.
- 17. Around the head and neck Desmognathus fucus carry their eggs around neck and its head. . Eggs coiled around neck of female
- 18. Coiling around eggs: The apodans such as Ichthyophis glutinosa lays eggs in a shallow hole near the water and the female coils herself around the gelatinous egg mass eggs
- 19. • In the Salamander congo eel Amphinuma the female lays large eggs in burrows in damp soil and guards them by coiling her body round them until they hatch. The female Plethodon also coils round the eggs. Transfering tadpoles to water : Some species of small frogs such as Phylobates, Arthroleptis, Pelobates in both Tropical Africa and South Americans deposits their eggs on ground.
- 20. The tadpoles hatching out from parents Eg- female in Sooglossus with their sticky ventral tropical Africa and South America deposits their eggs on ground.The tadpoles hatching out fasten themselves to the back of one of the parents Eg:female in Sooglosus with their sucker like mouth or their sticky ventral side. froglets
- 21. Eggs around the legs • Male Alytes obstitricans rap the rows of eggs around their legs and pelvic region and carries them till hatching.
- 22. Eggs on the back of the female Female Brazalian tree frog (Hyla goeldii) Carry eggs on their back. • Pipa americana eggs are carried on the back of the mother.But the skin thickens and grows round the eggs.Until each is enclosed in a dermal cell which is finally covered by a lid formed from the secretion of glands of the skin.
- 23. Pipa pipa (Surinam toad) the eggs are carried by female during breeding season. The fertilized eggs are attached to the soft and spongy back of the female. Eggs glued to the body Eggs on exposed belly of female Female Rhacophorus reticulates, of Ceylon carry their eggs on their belly Eggs in back pouches: Gastrotheca marsupial eggs are placed in a common pouch present below dorsal surface of body wall. Froglets Eggs
- 24. In mouth or gull pouch South American male frog Rhinoderma darwinii take eggs in gull pouch. The gull pouch is modified vocal sac. (These eggs emerge into young frog. Rhinoderma pushes at least two fertilized eggs in vocal sacs. Tadpoles complete their development and are metamorphosis in voal sacs. West African tree frog (Hylambates breviceps) female carries eggs in her buckle cavity. froglets Vocal sacs
- 25. Viviparity Pipa dorsigera, Pseudophryne vivipara and Nectopharycnoides trotnieri are viviparous.They give birth to young ones. Their embryos develops in their uterus. Embryo of pipa dorsigera get nutrition by pseudoplacenta. The European Salamandra salamandra produce 20 or more small young while alpine salamander S.atra. The eggs are placed inside the uterine cavity where the entire development takes place.The uterine wall functions physiologically as primitive placenta operculum Pseudoplacenta in Pipa dorsigers Cutaneous pouch Yolk sac Vascular tail
- 26. Conclusion • Parental care occurs 10-15% in Anurans exhibiting the greatest diversity. • It enhances the survival rate of eggs and larvae. • Protects from predators and desiccation. • Contributes to reproduction fitness.
- 27. References • David McFarland (1985) Animal Behaviour,Pitman Publishing limited,UK • Lee Alan Dugatkin Principles of Animal Behaviour Publisher:W.W.Norton • Manning, A and Dawkins,MS (2002 ) An Introduction to Animal Behaviour, Cambridge University Press,UK • Agarwal V.K (2009) Animal Behaviour S.Chand • Reena Mathur Animal Behaviour Rastogi publication