Question

Consider a typical bullfrog who lays thousands of eggs in water. Because there typically is no standing water inside bamboo, do you think the bush frog has adaptations in place to prevent the embryos from dying due to lack of water? Explain. What ideas can you think of to deal with the stress of dehydration?

Answer 1

Bullfrogs like most other frogs only reproduce during significant rainfall. Females then lay eggs in little temporary pools around the margins of large ponds. As many as 4000 eggs may be released and the eggs are fertilized above the water`s surface. These eggs require moisture to survive or will dry up and die. To prevent this the frogs eggs are surrounded by a special jelly-like glycoprotein that swells up on contact with water. Individual egg masses contain 10-85 eggs which measure 1 to 2 inches across. The jelly helps retain moisture and prevents the eggs from drying up. It also keeps the eggs together and forms a protective covering above them. The eggs can also absorb moisture and become much bigger after they are laid. Male frogs defend the egg until they hatch and it is observed that during times when the pool is near desiccation, the male digs up a channel to the nearby body of water to ensure a constant supply of water.The eggs hatch more quickly in warmer water, with the time averaging between two to three weeks.