Amphibian Reproductive Behavior and Strategies

  1. What is oogenesis?
    the formation, development, and maturation of an ovum (it is the development of eggs)
  2. In amphibians, what signals the development of eggs (oogenesis)?
    Courtship behaviors (mating calls or courtship dance)
  3. Courtship has never been observed/witnessed in which salamander family?
  4. Although courtship has never been observed, Sirenidae may reproduce using external fertilization. Explain why?
    Sirenidae does not have a spermatheca which suggests they reproduce using external fertilization.
  5. Although courtship has never been observed, Sirenidae may reproduce using internal fertilization. Explain why?
    Sirenidae females lay their eggs singly which suggests that they reproduce using internal fertilization.
  6. Name two salamander families that reproduce using external fertilization.
    Cryptobranchidae and Hynobiidae
  7. How does Cryptobranchus fertilize their eggs?
    The female releases a strand of eggs and the male follows behind her and fertilizes each egg. (Crypto males creep behind the females)
  8. Which salamander family does the females court the males? Explain their reproductive strategy.
    • Amphiumidae
    • As the female and male amphiumidae share a courtship embrace, the male releases a spermatophore. The spermatophore is picked up by the female's cloaca. Each egg is fertilized as they are being laid. (Internal fertilization)
  9. In temperate climates, breeding season is signaled by?
    Temperature and photoperiod
  10. In tropical climates, breeding season is signaled by?
  11. In salamanders, courtship usually occurs in water except in which two families?
    • Plethodontidae
    • Ambystomatidae (mole salamanders)
  12. Describe the general courtship behavior of salamanders:
    • 1.) The male approaches
    • 2.) A nudge is used to determine if the other salamander is a male or female
    • 3.) The male turns the female in the right direction and position (waltz)
    • 4.) The female follows behind the male and the male shakes his tail
    • 5.) The female nudges the male in the cloacal region to let him know that she is there
    • 6.) A spermatophore is dropped/deposited by the male
    • 7.) The male moves up one body length and the female follows until her cloaca is over the spermatophore
    • 8.) Her cloaca picks up the spermatophore
  13. Some members of these two families do not lay their eggs in water. Where do they lay their eggs?
    • Plethodontidae and Ambystomatidae
    • ~ Some lay their eggs on land. Once it rains the eggs hatch and the larvae stay in the puddle or make their way to a puddle
    • ~ Some eggs are laid in clusters above water
  14. European salamander, that usually has aquatic eggs and larvae, but some montane populations exhibit ovoviviparity.
    ~ Ovoviviparity is used due to the thermal pressure of the colder habitat
    ~ Keeping eggs in the mother allows her to chose appropriate temperatures for their development
    Salamandra salamandra
  15. Two salamander Genus species that exhibit viviparity
    • Salamandra salamandra
    • Salamandra atra
  16. Salamandra atra female exhibits an unique way of feeding her embryos. Explain.
    Only one or two eggs are fertilized in each oviduct. The other eggs are devoured by the embryos.
  17. What stimulates eggs to be shed by females?
  18. Amplexus
    • Typically lasts ~ an hour but some South American varieties amplex for months
    • Usually axillary with male forelimbs under female forelimbs
    • Places their cloaca regions in proximity
  19. ~Sexual size dimorphism
    ~Amplexus assisted by glue-like secretions of both male and female
    ~Male stuck up to 3 days
    ~Occurs on land, both dig with hindlimbs and create a wet nest for eggs
    • Breviceps spp.
    • Family- Microhylidae
  20. ~Sexual dimorphism
    ~Amplexus assisted by glue-like secretions
    ~Not as drastic Breviceps
    • Gastrophryne carolinensis
    • Family- Microhylidae
  21. Name two Genus of anurans that have internal fertilization
    • Nectophrynoides (6 species of the African genus)
    • Eleutherodactylus (a least 2 species)
  22. How do Nectophyrnoides and Eleutherodactylus accomplish internal fertilization?
    By moving cloacae adjacent to one another during amplexus
  23. What is the only frog with a true intromittant organ?
    Ascaphus truei
  24. The tailed frog from NWUS. The "tail" is actually an outgrown of the cloaca. Name the Genus species. Explain why these species have this adapation.
    • Ascaphus truei
    • The adapation is for reproduction in swift running stream habitats
  25. Which Genus of anurans has some species that exhibits both ovoviviparity (several species) and viviparity (2 species)?
  26. Which Genus of anurans has some species that exhibits ovoviviparity?
  27. Which family of anurans lay their eggs in masses that are spread at the surface of warmer waters with less oxygen? (usually late in the season)
  28. Which family of anurans lay their eggs in clumps as long as the water is cold enough to hold suffcient oxygen?
  29. Which family of anurans lay their eggs in strands/chains in temporary ponds that have warm water?
  30. ~Lay eggs on leaves, sometime the leaf is wrapped around to slow water loss
    ~ Some species periodically empty their bladder to keep eggs moist
    ~ Some unfertilized eggs serve as water capsules
    ~ Tadpoles hatch and drop into water below
    Name the anuran family and where they are from.
    • Family- Hylidae
    • South America
  31. Name the four anuran families that produce foam nests.
    • Lepodactylidae (South and Central America)
    • Myobatrachidae (Australia)
    • Rhacophoridae (Africa)
    • Hyperoliidae (Africa)
  32. Describe foam nests
    • Foam nests are produced when females or males or both (depending on species) rub their hindlimbs together releasing both the foam and spawn
    • The foam dries and resists dehydration
    • Tadpoles drop into the water below once they hatch
    • The foam nests can be found on the water's surface, on vegetation, and in mud at the edge of water
  33. Inguinal amplexus
    male holds the female at the waist just anterior to her hind legs
  34. ~Dorsal brooding
    ~As female turns over, batches of eggs are released which move towards the male's vent.
    ~Male pulls up legs (eggs follow) then he presses them into her back while fertilizing them
    ~Entire process may take over 300 turnovers
    ~Eventually epithelium grows up around them
    ~ Hatch as froglets
    Name Genus species and Family
    • Pipa pipa (Surinam toad)
    • Family- Pipaidae
  35. What male anuran carries eggs on his back until they hatch?
    • Alytes obstetricans (European Genus)
    • Family- Discoglossidae
  36. ~Gastric brooding
    ~Eggs are fertilized externally and the mother devours them
    ~Eggs and tadpoles release prostaglandin E2 to block production of stomach acids
    ~At least one species thought to be extinct
    Name Genus species and Family
    • Rheobatrachus spp. (Australia)
    • Family- Myobatrachidae
  37. ~Eggs laid on land and guarded or tended to by the males
    ~Tadpoles gathered in male's buccal cavity and taken to small pools of water to develop
    Name the Genus species and Family
    • Rhinoderma rufum
    • Family- Rhinoderatidae
  38. ~Eggs laid on land and guarded or tended to by the males
    ~Tadpoles taken into buccal cavity, then into vocal sacs and brooded until froglets
    Name Genus species and Family
    • Rhinoderma darwinii
    • Family- Rhinodermatidae
  39. Several species of frogs from South and Central America lay eggs on land
    ~Then the male or female (depending on the species) allows tadpoles to wiggle up onto their back and transport them to water.
    Name the Family
  40. ~The mother picks up the tadpoles after they have hatched and transports each to its own bromeliad
    ~She visits periodically over the next 6-8 weeks and deposits unfertilized eggs which the tadpoles eat
    Name Genus species and Family
    • Dendrobates pumilio
    • Family-Dendrobatidae

    The family Hylidae has similar habits
  41. ~Not much has be observed with courtship (assumed to be simple or absent)
    ~Males of all species possess an intromittant organ called a phallodeum so all are assumed to have internal fertilization
  42. Caecilians possess an intromittant organ called...
  43. Some caecilians are ____________ and females usually __________ the eggs
    • oviparous
    • guard
  44. Caecilian eggs are deposited at the __________ __________ and ________ make their way to the water
    • water's edge
    • larvae
  45. What % of caecilians are viviparous?
Card Set
Amphibian Reproductive Behavior and Strategies