Reproduction Flashcards
Generally, how does sexual dimorphism present in amphibians?
Females larger than males.
Differences in coloration in some species.
Larger and more pigmented vocal sacs of male frogs.
Cloacal glands in male salamanders swollen, with enlarged cloacal lips.
Male plethodontid salamanders develop enlarged hedonic glands on chin which are rubbed on female.
Male frogs develop keratin pads on thumbs to assist in amplexus (characteristic prolonged breeding embrace).
Enlarged teeth in males
Which frogs have a tympanum that is larger than the eye?
Male bullfrogs, pig frogs, and bronze frogs.
What type of fertilization occurs in many salamanders? Frogs?
Internal. External.
What frog species carries her eggs on her back, with skin growing over the eggs?
Surinam toad (Pipa parva) a relative of Xenopus
Do amphibians provide parental care?
Yes, some species.
What parental care does the Midwife toad (Alytes obstetricans) provide?
Wraps the strands of fertilized eggs around his legs. Carries the eggs with him, visiting ponds periodically to keep them moist until hatching.
What factors regulate reproduction in amphibians?
Arginine vasotocin.
In some species, temp is more important than photoperiod.
Increasing day length in axolotl light cycle encourages breeding.
Generally, where do larval amphibians live? Describe their general characteristics.
In water. Have gills, lack eyelids. Skeleton primarily cartilaginous. Dorsal and ventral fins present, with muscled tail and body. Lateral line system in all amphibian larvae.
How does the appearance of larval amphibians compare to adults?
Salamander larvae closely resemble adults, with four limbs.
Premetamorphic tadpoles appear very different, with fleshy oral disk. No teeth, with horny beak and denticles that rasp and cut. Gills initially external, but covered, along with forelimbs, by operculum. Hindlimbs late in larval period.
When does cannibalism in amphibians develop more slowly?
If sibling larvae are housed together exclusively.
What does metamorphosis require? What factors can result in early metamorphosis?
Presence of thyroid hormone and iodine. Crowding and reduced feed availability can stimulate early thyroxine release and result in early metamorphosis.
What is the metamorphic climax? What occurs at this time?
Time immediately before emergence. Tail resorbed, forelimbs break through operculum, and hindlimbs become functional.
What husbandry measures should be provided during the metamorphic climax?
Decrease water levels and provide a ramp or other object to facilitate emergence to a terrestrial existence. Can drown.
How does metamorphosis affect the immune system?
Time of immune stress. Larvae that undergo metamorphosis at less-than-optimal size become IS.
