Agalychnis callidryas (Cope, 1862)

General Recognition

Agalychnis callidryas is easily recognizable by its colorful appearance.

Sexual Size Dimorphism

Males reach about 2 inches in length, while females grow to 3 inches, making females the larger of the two sexes.

Base Body Coloration

Adult individuals have distinctive coloration: bright green bodies, light blue or cream-colored bellies, and blue and yellow stripes along their sides.

Foot Structure

Their feet are bright orange and have suction cups that help them adhere to the undersides of leaves, where they spend most of their time.

Skin Texture

Their skin is smooth with little to no bumps, a feature that helps the frog blend into its leafy surroundings.

Skin Gland Function

A gland on the outermost layer of its skin secretes mucus to resist water loss and provide some defense against infections.

Eye Appearance

One of its most striking features is its bright red eyes with vertical slits.

Eyelid Adaptation

This species does not have a true eyelid; instead, it has a nictitating membrane that allows light to enter the eye, so the frog will awaken when predators approach.

Flash Coloration Definition

The frog's coloration is an example of flash coloration, a pattern where an organism displays different colors at rest versus when in motion.

Resting Camouflage

For red-eyed tree frogs, the startling red eyes are hidden when the eyes are closed, letting the frog blend in with surrounding leaves.

Startle Display Components

When the frog is startled, it can flash its bright red eyes, orange webbed feet, and blue and yellow lateral stripes.

Startle Display Function

This display startles predators, giving the frog time to escape.

Coloration Toxicity Status

Despite its bright coloration, this coloration does not indicate toxicity or aposematism, unlike the coloration of some related tree frog species.

Geographic Color Morph Variation

While the main body coloration of Agalychnis callidryas is consistent across the species, there are color morph variations across its geographical range.

Side Stripe Morph Examples

Variation occurs specifically in the color of the side stripes: in Costa Rica and Panama, these stripes can be blue, blue-red, orange, or purple.

Base Color Camouflage Function

The species' green base color helps it blend easily into the vegetation of tropical rainforests.

Color Morph Hypotheses

There are multiple hypotheses for why these color morphs exist.

Isolation By Distance Hypothesis

One well-supported hypothesis states that orange and purple morphs in Costa Rica exist due to isolation by distance, as these morphs are not genetically distinct groups.

Alternative Morph Origins

It is also possible that different selective pressures have shaped color patterns, and that some morphs exist due to genetic drift.

Geographical Range

Agalychnis callidryas is native to Central America, ranging from northeastern Honduras to northern Colombia.

General Habitat Types

Its natural habitats include inland tropical and mountainous forests and wetlands, where there is forest cover and water nearby.

Water Requirement

Ponds or other bodies of water are essential for its reproduction, so the species is always found near these areas.

Common Habitat Location

It is commonly found in the tropical rainforests of the listed countries.

Arboreal Preference

The species is primarily arboreal, and prefers hiding in canopy cover among leaves.

Humidity Requirement

It requires high humidity levels of at least 80%.

Mating Season Timing

Red-eyed tree frogs mate seasonally, during the rainy season from October to March.

Male Reproductive Competition

Males attract females by croaking, and wrestle with each other in male-male competition to gain access to females for reproduction.

Female Behavior During Competition

Females cling to the underside of a leaf using the suction cup-like structures on their webbed feet, and must hold on while nearby males compete and wrestle.

Amplexus Process

After a male wins the competition, the pair engages in amplexus, where the male grasps the female by the waist from behind.

Egg Laying And Fertilization

The female lays eggs on the underside of the leaf as the male fertilizes them.

Typical Egg Hatching Time

If undisturbed, eggs typically hatch within 6 to 7 days.

Oviposition Location Purpose

This oviposition happens above or very close to a body of water, because newly hatched tadpoles drop from the leaf into the water below.

Early Hatching Trait

Eggs can hatch early if their survival is threatened, a trait called phenotypic plasticity.

Clutch Size And Placement

The female chooses a leaf above a pond or large puddle to lay her clutch of roughly 40 eggs.

Egg Protection Behaviors

Since oviposition can occur on either side of a leaf, red-eyed tree frogs may fold the leaf to hide eggs from predators.

Egg Jelly Function

They also produce sticky jelly to glue the eggs together, which may protect eggs from splitting and dehydration.

Multiple Clutch Capacity

After fertilization, females lay clutches of about 40 eggs, and can lay multiple clutches in a single night.

Tadpole Entry To Water

Because eggs are adhered to a leaf above water, tadpoles fall into the water below immediately after hatching.

Hatching Time Variation

Eggs usually hatch 6–8 days after being laid, with some variation based on geography and risk detection through vibration.

Larval Stage Duration Range

Depending on environmental conditions, tadpoles stay in the water for a few weeks to several months.

Post-Metamorphosis Traits

After metamorphosis, they develop the adult color pattern, and live for about five years in the wild.

Hatching Timing Cue

Red-eyed tree frog embryos use natural day and night light cycles as a hatching signal, and most often hatch just after nightfall.

Tadpole Predators

Dragonflies, fish, and water beetles prey on tadpoles.

Tadpole Development Period

Tadpoles remain in the water from three weeks to several months, until they metamorphose into adult frogs.

Metamorphosis Timing Drivers

The timing of metamorphosis depends on the length of the larval stage, which varies based on environment.

Metamorphosis Color Changes

After metamorphosis, the torso color of tadpoles changes from green to brown, and their initially yellow eyes turn deep red, with little side patterning developing.

Sexual Maturity Markers

These changes mark sexual maturity.

Overall Lifespan

The overall lifespan of red-eyed tree frogs is about five years.