Red-eyed tree frog | |
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In Costa Rica | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Amphibia |
Order: | Anura |
Family: | Hylidae |
Genus: | Agalychnis |
Species: | A. callidryas |
Binomial name | |
Agalychnis callidryas (Cope, 1862) | |
Synonyms | |
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Agalychnis callidryas, commonly known as the red-eyed tree frog or red-eyed leaf frog, is a species of frog in the subfamily Phyllomedusinae. It is one of the most recognizable frogs. 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. One particular and special feature of the frogs coloration is its exceptional high reflectance in the near-infrared. [3]
Agalychnis callidryas 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. [4]
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 A. callidryas. If faced with the vibrational cues associated with predators, A. callidryas 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 rainforests of South and Central America.
Agalychnis callidryas 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. [5] 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. [5] Their skin is smooth with little to no bumps, another feature which helps the frog blend into their leafy surroundings. Additionally, they have a gland that secretes mucus on the outermost layer of their skin to resist water loss and offer some defense against infections. [6] 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. [7]
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. [8] 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. [9] Although the frog is brightly colored, this does not convey toxicity or aposematism as it may in related tree frog species.
Though the main coloring of Agalychnis callidryas 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. [10] Red-eyed tree frogs blend in easily with the vegetation of tropical rainforests due to them being green color. [11] 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. [10]
As a species of tree frog, Agalychnis callidryas has a claw shaped terminal phalanx. [12] Other synapomorphies of this genus include the presence of a red hue on the iris and a golden reticulated palpebral membrane. [13]
Agalychnis callidryas is native to Central America, from northeastern Honduras to northern Colombia. [14]
Its natural habitats include inland forests and wetlands, both tropical and mountainous areas where there is forest cover and water nearby. [15] 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. Agalychniscallidryas require high humidity levels of at least 80%. [16]
Adult red-eyed tree frogs are primarily carnivores, eating crickets, moths, grasshoppers, flies, mosquitoes, and other insects. [17] Occasionally, they also eat smaller amphibians. Tadpoles eat plants, algae, plankton, bacteria, carrion, and their fellow tadpoles. [17] [18] After metamorphosis, froglets begin consuming small insects like fruit flies and pinhead crickets. [19] A study on carotenoids consumption has shown they play an important role in development, phenotype, and fecundity. [20] There is a critical window after metamorphosis where carotenoids improve female growth rate and fecundity, and lead to a redder skin in both sexes. Carotenoids are important nutrients for wild red-eyed tree frogs and especially for captive red-eyed tree frogs, who sometimes suffer skin pigmentation degradation due to an inadequate diet.
Red-eyed tree frogs mate seasonally, specifically in the rainy season during the months of October to March. [21] Males attract females by croaking and wrestle with each other in male-male competition in order to gain access to females for reproduction. [22] Females latch on to the underside of a leaf using the suction cup like structures on their webbed feet, and the female must hold on to the leaf while males compete and wrestle nearby. The winning male and female will then participate in amplexus, where the male will grasp a female by the waist from behind. [23] The female will lay eggs on the underside of the leaf as the male fertilizes them. [21] The eggs typically hatch within 6 to 7 days if left undisturbed. [24] This process occurs above or very close to a body of water, because tadpoles which hatch from the eggs will drop into water from the leaf. Eggs will hatch early if their survival is threatened, in a process called phenotypic plasticity. The female chooses a leaf above a pond or large puddle on which to lay her clutch of roughly 40 eggs. Since oviposition generally occurs on both sides of a leaf, red-eyed tree frogs may fold the leaf to hide the eggs from predators. They also produce sticky jelly to glue the eggs together; this may protect the eggs from splitting and dehydration. [25]
Following fertilization, females lay clutches of about 40 eggs, and can lay multiple clutches in a single night. Since the eggs are often adhered to a leaf above water, tadpoles fall into the water below as soon as they hatch. Eggs will usually hatch 6–8 days after they have been laid, with some variation depending on geography and risk assessment through vibration. [26] Depending on environmental conditions, the tadpoles will then stay in the water for a few weeks or months. They will change to adult colors following metamorphosis, and live for about five years in the wild. [24]
Red-eyed tree frog embryos use natural day and night light cycles as a signal for when to hatch, and tend to hatch just after nightfall. [27] Red-eyed tree frog eggs may hatch early (exhibiting phenotypic plasticity) when a change in the environment signals a danger to their survival. [28] Dragonflies, fish, and water beetles prey on the tadpoles. The tadpoles remain in the water from three weeks to several months, until they metamorphose into frogs. The time of metamorphosis depends on duration of larval stage, which varies depending on environment. After metamorphosis, the color of tadpoles' torsos changes from green to brown, and their eyes, which are initially yellow, turn into deep red without much side patterning. These changes mark maturity. The lifespan of red-eyed tree frogs is about five years. [29]
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. [30] 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. [31] 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. [32] 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. [33] 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 Agalychnis callidryas, and so a single clutch of eggs may have been fertilized by multiple males. [34]
Red-eyed tree frogs' embryos exhibit phenotypic plasticity, hatching early in response to disturbance to protect themselves. Though embryos are bred synchronously, they normally hatch after 6 to 10 days from oviposition without disturbance. [25] However, a simultaneously early hatching in entire clutches is triggered when embryos are exposed to their predators or threatening environmental changes such as rainstorm and flood. [25] [35] Early hatching has also been linked with egg dehydration, hatching earlier in dry egg clutches than in wet ones. [36]
Hatching early is an important defense to predators, but is also a risky strategy for embryos because early hatching increases predation risk in water. [37] Therefore, to maximize the benefits of this strategy embryos must only hatch when they are truly at risk by a predator. Studies show that this strategy is multifaceted and a specific combination of vibrational pulse duration and inter-pulse intervals is needed in order for embryos to exhibit this response. [38] This combination of pulse duration and inter-pulse intervals is thought to be specific to the embryo predators, thus ensuring the response only occurs when absolutely necessary to ensure survival.
Predators are the major cause of this response. Since these frogs usually lay eggs on both the upper and the undersides of leaves above ponds, clutches need to protect themselves against arboreal, aerial and aquatic predators, such as snakes, dragonflies, fish, monkeys, and pathogenic fungi. [39] When predators are close enough to produce detectable vibration, the embryos assess disturbance. After a few seconds, embryos vigorously hatch out into tadpoles and spread out to escape. [25] [40] Since eggs are usually laid above ponds, the response improves survival because tadpoles often fall into water on hatching. Hatching direction also has implications on embryo survival. Embryos often hatch and fall into the water, but hatching direction may also be influenced by light. A study found that A. callidryas embryos hatch towards light, suggesting they use light and dark as directional cues to determine hatching direction. [41]
As of 2016, the red-eyed tree frog is classified as being of least concern. While the population is decreasing, and inhabits many areas vulnerable to deforestation, the classification of “least concern” stems from its general tolerance to habitat modification, a wide species distribution, and presumably large captive population. The red-eyed tree frog's husbandry, care, and breeding knowledge have been greatly improved upon in the 21st century. [42] [43] However, as with all frogs and toads, the species still faces challenges from chytrid fungus, logging, and residential development. Wild tadpoles have experienced die-offs due to ranavirus, and subpopulations in Costa Rica, Nicaragua and Panama are threatened by capture for the international pet trade. [44]
Edalorhina perezi is a species of frog in the family Leptodactylidae. It is one of the only two species in the genus Edalorhina in the family Leptodactylidae. This species is diurnal and terrestrial. During mating season both female and male frogs gather around treefall pools. It is found in Brazil, Colombia, Ecuador, and Peru, and possibly Bolivia. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, and freshwater marshes. The species listed as least concern on the IUCN Red List and the population is stable.
The glass frogs belong to the amphibian family Centrolenidae, native to the Central American Rainforests. The general background coloration of most glass frogs is primarily lime green, the abdominal skin of some members of this family is transparent and translucent, giving the glass frog its common name. The internal viscera, including the heart, liver, and gastrointestinal tract, are visible through the skin. When active their blood makes them visible; when sleeping most of the blood is concealed in the liver, hiding them. Glass frogs are arboreal, living mainly in trees, feeding on small insects and only coming out for mating season. Their transparency conceals them very effectively when sleeping on a green leaf, as they habitually do. However, climate change and habitat fragmentation has been threatening the survival rates of the family.
The American green tree frog is a common arboreal species of New World tree frog belonging to the family Hylidae. This nocturnal insectivore is moderately sized and has a bright green to reddish-brown coloration. Commonly found in the central and southeastern United States, the frog lives in open canopy forests with permanent water sources and abundant vegetation. The American green tree frog is strictly aquatic during the hibernating and mating seasons. When defending its territory, the frog either emits aggressive call signals or resolves to grapple with intruders, seldom leading to injury or death. To avoid predation, the frog will leap into the water or jump into the treetops.
The Pacific tree frog, also known as the Pacific chorus frog, has a range spanning the Pacific Northwest, from Northern California, Oregon, and Washington to British Columbia in Canada and extreme southern Alaska. They live from sea level to more than 10,000 feet in many types of habitats, reproducing in aquatic settings. They occur in shades of greens or browns and can change colors over periods of hours and weeks.
Bibron's toadlet or brown toadlet is a species of Australian ground-dwelling frog that, although having declined over much of its range, is widespread through most of New South Wales, Victoria, south-eastern Queensland, and eastern South Australia, including Kangaroo Island. Bibron's toadlet settles in a wide variety of habitats within these region but they mainly reside in dry forests, woodland, shrubland, grassland, coastal swamps, heathland, and sub-alpine areas. They deposit their eggs in leaf litters during the flooding season, which is essential for the proper development of the egg. This species has high sexual dimorphism within the species and utilizes chemosignals to attract potential mates.
Phyllomedusa bicolor, the giant leaf frog, bicolor tree-frog, giant monkey frog, or waxy-monkey treefrog, is a species of leaf frog. It can be found in the Amazon basin of Brazil, Colombia (Amazonas), Bolivia, and Peru, and can also be found in the Guianan Region of Venezuela and the Guianas, and in Cerrado of the state of Maranhão in Brazil.
Phyllomedusa sauvagii, the waxy monkey leaf frog or waxy monkey tree frog, is a species of frog in the subfamily Phyllomedusinae. It is native to South America, where it occurs in Argentina, Bolivia, Paraguay and Brazil. This species is arboreal, living in the vegetation of the Gran Chaco.
Hyalinobatrachium fleischmanni, also known as Fleischmann's glass frog or the northern glass frog, is a species of frog in the family Centrolenidae. It is found in the tropical Americas from southern Mexico to Ecuador. Specifically, these frogs occur in Mexico, Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama, Colombia, and Ecuador. It has often been confused with related species, and the exact distribution depends on the source. This frog tends to have green skin, pale yellowish spots, yellow fingertips and translucent skin covering its stomach.
Morelet's tree frog, also known as black-eyed leaf frog and popeye hyla, is a species of frog in the subfamily Phyllomedusinae. It is found in Belize, El Salvador, Guatemala, Honduras, and Mexico.
Agalychnis saltator, also known as the parachuting red-eyed leaf frog and misfit leaf frog, is a species of frog in the subfamily Phyllomedusinae. It is found in the Caribbean lowlands from north-eastern Honduras to eastern-central Costa Rica at elevations of 15–1,300 m (49–4,265 ft) asl.
Dendropsophus ebraccatus, also known as the hourglass treefrog, referring to the golden-brown hourglass shape seen surrounded by skin yellow on its back. Their underbellies are yellow. Their arms and lower legs usually display bold patterns while their upper legs or thighs are light yellow giving them the appearance of wearing no pants. The species name "ebraccata" translates to "without trousers" in Latin.
The pine woods tree frog is a species of frog in the family Hylidae, endemic to the southeastern United States.
Agalychnis lemur, the lemur leaf frog or lemur frog, is a species of frog in the subfamily Phyllomedusinae. It is found in Costa Rica, Panama, and adjacent northwestern Colombia. It is classed as Critically Endangered and threatened by the fungal disease chytridiomycosis.
The emerald-eyed tree frog is a species of frog in the family Hylidae. It is largely restricted to the Atlantic Forest region of Brazil. Some populations previously regarded as Boana crepitans have been separated into the species Boana xerophylla and Boana platanera.
The green-eyed treefrog is a species of Australasian treefrog in the subfamily Pelodryadinae that occurs in the Wet Tropics of Australia.
Phyllomedusa trinitatis is a species of frog in the subfamily Phyllomedusinae. It is found in Venezuela and the island of Trinidad.
Edalorhina perezi is a species of frog in the family Leptodactylidae. It is one of the only two species in the genus Edalorhina in the family Leptodactylidae. This species is diurnal and terrestrial. During mating season both female and male frogs gather around treefall pools. It is found in Brazil, Colombia, Ecuador, and Peru, and possibly Bolivia. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, and freshwater marshes. The species listed as least concern on the IUCN Red List and the population is stable.
The grey foam-nest tree frog, or southern foam-nest tree frog, is a species of frog in the family Rhacophoridae. They are found in southern Africa.
Zhangixalus moltrechti is a species of frog in the family Rhacophoridae. It is endemic to Taiwan, where it has a wide distribution in hilly areas. Common names Moltrecht's green treefrog, Moltrecht's treefrog, Taiwan treefrog, and Nantou flying frog have been coined for it.
Agalychnis taylori, commonly known as the red-eyed tree frog or Taylor's leaf frog, is a species of frog in the subfamily Phyllomedusinae. It was originally described as a subspecies of Agalychnis callidryas in 1957. In 1967 it was synonymized with Agalychnis callidryas by Savage and Heyer. In 2019, it was resurrected and elevated to a full species based on well-supported morphological data. The range of Agalychnis taylori extends from central Veracruz, Mexico, to west-central Honduras.