Male red-eyed treefrog, Corcovado National Park, Costa Rica

Recently hatched tadpole

Red-eyed treefrogs live in lowland wet forest from the Yucatan through Panama. They lay their eggs on vegetation over water, and when tadpoles hatch, they fall into the water. Embryos are exposed to arboreal and aerial predators and pathogens. Tadpoles face a different set of risks, including predatory invertebrates and fish.

Cat-eyed snake, Leptodeira septentrionalis,

one of four species that eats A. callidryas eggs

A social wasp, Polybia rejecta, taking an embryo

... and pathogens

Egg-killing fungus (Dothideales) attacking an embryo

aquatic vertebrates ...

A poeciliid fish, Brachyraphis rhabdophora, that occurs in some red-eyed treefrog ponds, and eats tadpoles

Backswimmer eating a red-eyed treefrog tadpole

Red-eyed treefrog hatchling fleeing from a freshwater shrimp,

Macrobrachium americanum

Adaptive plasticity in hatching

Red-eyed treefrog embryos hatch at different ages, and developmental stages, depending on conditions in the egg. Safe embryos hatch relatively late, when they are more developed and better able to escape from aquatic predators. Embryos attacked by snakes, wasps, or fungus, or threatened with drowning, hatch early to escape. At Gamboa, Panama, the typical undisturbed embryonic period is 6 or 7 days, but embryos hatch as early as 4 days if threatened by egg-stage risks. In Corcovado National Park, Costa Rica, embryos hatch undisturbed at 7 or 8 days of age, but hatch as early as 5 days old if attacked.

LEFT: Newly hatched tadpoles of A. callidryas.

TOP: Induced early hatching (5 d, Corcovado).

BOTTOM: Normal undisturbed hatching (7 d, Corcovado).