The Red Eyed Tree Frog

 From Wikipedia

Edited by -Amal Udawatta,

The red-eyed tree frog (Agalychnis callidryas), is a species of frog in the subfamily Phyllomedusinae. It is native to forests from Central America to north-western South America. This species is known for its bright coloration, namely its vibrant green body with blue and yellow stripes on the side. It has a white underside, brightly red and orange colored feet, and is named after its distinctive bright red eyes.

Red eyed tree frog is an arboreal frog with long limbs and webbed toes. They mate and reproduce near ponds, and are therefore found in lowland wet areas found in tropical forests

Like all the frogs in its genus, they are nocturnal and do most of their hunting for insects at night. The males of this species are smaller than the females, and they display non-random mating patterns which suggest female choice for specific types of male. Despite its bright coloration, the red-eyed tree frog is not poisonous. Its bright coloration can thus be more attributed to camouflage amongst the greenery of the surrounding jungle, as well as the “startle reflex,” which it can use to dissuade predators. During the day, the frog uses its green back to camouflage amongst the leaves, this camouflage being its only defense. If disturbed, the frog flashes its bright red eyes, which may startle predators and allow the frog to escape.

Along with its visual appearance, phenotypic plasticity in hatching is another interesting feature of Red eyed tree frog . If faced with the vibrational cues associated with predators, . Red eyed tree frog  embryos may hatch early and fall into the water to escape predation. This response is extremely specific, and mostly occurs only at vibrational patterns associated with predators. These frogs have a distinct temperature requirement and need a body of water to reproduce, and are thus only found in humid lowlands and rain forests of South and Central America.

Red eyed tree frog  is an easily recognizable species due to its colorful appearance. In terms of size, males reach about 2 inches while females grow to 3 inches and are the larger of the two. Adult individuals are distinctively colored, with bright green bodies, light blue or cream colored bellies, and blue and yellow stripes along their sides. Their feet are bright orange and have suction cups which help them adhere to the bottom of leaves where they spend most of their time. Their skin is smooth with little to no bumps, another feature which helps the frog blend into their leafy surroundings. An impressive feature is their bright red colored eyes with vertical slits. They do not have a true eyelid, but rather a nictitating membrane that allows light to enter the eye so that they will awaken when predators are approaching.

The frog's coloration is representative of “flash coloration.” Flash coloration describes when an organism displays certain colors at rest compared to when in motion. In the red-eyed tree frog’s case, the frog’s startling red eyes are hidden when its eyes are closed allowing it to blend in with leaves. When the frog is startled, it can flash its bright red eyes, orange webbed feet, and blue and yellow lateral stripes, which all serve the purpose of startling predators and allowing the frog time to escape. Although the frog is brightly colored, this does not confer toxicity or aposematism like it may in related tree frog species.

hough the main coloring of Red eyed tree frog  is consistent, there are some variations in morphs across the geographical range of the species. Red-eyed tree frogs have variation in the color of their side stripes, which in Costa Rica and Panama specifically includes blue, blue/red, orange and purple. There are several hypotheses for the reason behind the existence of these color morphs. One strong hypothesis is that the existence of orange and purple morphs in Costa Rica are caused by isolation by distance, because the orange and purple morphs were not genetically distinct groups. It is possible that color patterns have been affected by different selective pressures, and that the existence of some morphs are due to genetic drift.

Its natural habitats include inland forests and wetlands, both tropical and mountainous areas where there is forest cover and water nearby. Ponds or bodies of water are essential in its reproduction so they are always found near these areas. The red-eyed tree frog is commonly found in tropical rainforests in the previously listed countries. The frog is primarily arboreal, and prefers hiding in canopy cover amongst leaves. Red eyed tree frog  require high humidity levels of at least 80%.

Red-eyed tree frogs females are typically choosy about which males they mate with. Females will choose mates based on visual and auditory clues, mainly the male frogs’ croaking calls as well as their size and flank stripe. Females are likely to choose males with “local” flank stripes and call patterns, meaning that male frogs from nearby areas are selected for in mating. Call and stripe patterns are considered simultaneously by females in this situation. Size plays a role in mate choice for red-eyed tree frogs as well. Often larger males are more successful in amplexus compared to smaller males. However, size-assortative mating also plays a role and larger females are more likely to pair with proportionally large males and vice versa for small females and males. This is so the male can successfully fertilize the female’s eggs during amplexus.

During the mating season, the male frogs shake the branches where they are sitting to improve their chances of finding a mate by keeping rivals at bay. This is the first evidence that tree-dwelling vertebrates use vibration to communicate. When rainfall is at its highest, a male red-eyed tree frog calls "chack" to get the attention of the female. Females use the call, as well as color (specifically, the stripped sides) of the male frog, in order to find a possible mate. Both the call and color of the male frog show territorial display, and anti-predatory behavior. During amplexus, the female carries the male on her back for several hours during the oviposition process. Because of external egg fertilization, there is still risk of competition even after a female has selected a mate. There is not sperm priority in Red eyed tree frog  and so a single clutch of eggs may have been fertilized by multiple male.