DEEP: Larval Cycles

Larval Cycles

Typical Mole Salamander (Ambystoma) Larval Cycle

{Vernal Pool}   {spermatophores}
Vernal pools, small depressions in the forest, fill with snowmelt and water over the winter and early spring.   Male salamanders migrate to vernal pools under the cover of darkness during early spring rains and deposit spermatophores on the bottom of the pools.
{Frog Eggs}   {Frog Larvae}
Females enter the pond during nighttime rains, engage in courtship, and are fertilized by picking up the spermatophores. They then deposit clumps of jelly-coated eggs.   Bushy-gilled larvae hatch. They are voracious feeders and develop rapidly for several months.
{metamorphs}   {Dried Up Vernal Pool}
Larvae metamorphose in mid to late summer. The pattern of these newly-transformed metamorphs differs from adults. Adult patterns appear several weeks to months after metamorphosis.   Vernal pool dries up in mid to late summer. This is an important part of the life cycle as fish cannot live in these pools and compete with and/or eat the salamander larvae.
Salamander Larvae
Salamander larvae also come in various sizes, but follow one of two basic forms.
{Spotted Salamander} {Two-Lined Salamander}
Vernal pool and pond dwelling larvae, as evidenced by this Spotted Salamander, have bushy gills, an adaptation for oxygen poor waters. Contrast this to this Two-Lined Salamander, a stream dwelling species characterized by very small gills because it lives in highly oxygenated water.

Frog Reproduction
Connecticut’s toads and frogs all reproduce in a similar manner as illustrated by these photographs of the Eastern American Toad.

{Calling Males} {Female in Amplexus}
Calling males gather, often in large numbers, forming choruses in wetlands. These choruses attract females to the males. Once the females are near the males, the male grasps the female in amplexus.
{Vented Eggs} {Hatching Tadpoles}
Coupled pairs deposit eggs. The male fertilizes the eggs as they are extruded from the female’s vent. These eggs are laid in strings, characteristic of toads. Most frogs lay clumps of eggs on the surface of the pond, some lay single eggs. Tadpoles hatch. They can, depending on species, take several weeks to several years to transform. Note the musk turtle superbly camouflaged at the edge of this shallow pond.
Tadpoles
Tadpoles come in various sizes, but generally follow one of two basic forms.
{Shallow Water Tadpoles} {Deep Water Tadpoles}

Tadpoles of the spring peeper, gray treefrog, and wood frog are adapted for living in shallow, still water. Their caudal fins are high compared to their overall body length.

Most tadpoles, like this bullfrog, are elongate and streamlined, adapted for living in deeper aquatic environments.

Amphibians and Reptiles in Connecticut