Red-eyed tree frog

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Red-eyed tree frog
Red eyed tree frog edit2.jpg

Red- eyed tree frog ( Agalychnis callidryas )

Systematics
Order : Frog (anura)
Subordination : Neobatrachia
without rank: Tree frogs (arboranae)
Family : Griffin frogs (Phyllomedusidae)
Genre : Red- eyed tree frogs ( Agalychnis )
Type : Red-eyed tree frog
Scientific name
Agalychnis callidryas
( Cope , 1862)

The Rotaugenlaubfrosch ( Agalychnis callidryas ) is the most famous and eponymous representative of the red-eyed tree frogs ( Agalychnis ) within the family of phyllomedusinae (Phyllomedusidae). The griffin frogs are one of three families of tree frogs , which used to be grouped together in the family of tree frogs . In the systematic overview, 13 Agalychnis species are currently distinguished, which are native to the Neotropics of Central and South America.

features

As is typical of griffin frogs, red-eyed tree frogs appear very lean and long-limbed. With head-torso lengths of a maximum of 59 millimeters for the males and 77 millimeters for the females, they are medium-sized tree frogs. The vertically slit-shaped pupils of the very large, laterally aligned eyes, which are round in the dark, contrast with the often strong red color of the iris (in freshly metamorphosed young frogs, the iris is initially more yellow). The overall body colors are also often very intense and rich in contrast, although some regional differences can be observed. The smooth-skinned upper side is usually light green during the day and a little darker green during nocturnal activity, while the flanks and parts of the upper extremities are colored blue, purple or brownish and the sides are typically criss-crossed with cream-colored or yellow stripes (transverse bands). The hands and feet have a bright orange color, end in moderately large adhesive discs and half to two thirds of the toe lengths are connected with tension skins. The ventral side is whitish. The skin of the red-eyed tree frogs and other griffin frogs is not nearly as poisonous as that of the tree diver frogs (Dendrobatidae), but it does contain a high concentration of various biologically active peptides , among other things to protect against skin diseases.

Sleep posture during the day

In the resting and sleeping posture that is characteristic of tree frogs, with legs close to the trunk and (half) closed eyes, the parts of the body that act as warning or frightening colors are not visible, only the green areas of skin. When the eyes are closed, the so-called nicks are used, which are transparent and have a gold-colored mesh running through them. They still allow the animals a certain perspective while at the same time protecting or camouflaging the conspicuous eyes. (In addition, the eyeballs can be drawn into the head.) The males form a rough heat callus on the inner finger that is helpful for mating and have slightly larger eardrums than the females. They also have paired glottis and an internal throat sound bladder .

distribution and habitat

Agalychnis callidryas is common in Central America; its area extends from southeast Mexico ( Yucatán ) in the north to the Colombian border of Panama in the south. In addition, there is an isolated occurrence in the Botanical Garden of Cartagena in northwestern Colombia. There are populations both on the Atlantic / Caribbean side of the Central American land bridge and on the Pacific side - here in Nicaragua and Panama. Primarily lowland rainforests are populated, but also the wooded slopes of adjacent mountain ranges. Premontane altitudes of up to 1250 meters can be reached. In addition to tree-dominated vegetation, the habitat also includes temporary and persistent water points (ponds, etc.). The range of the species is climatically one of the semi-humid to humid warm tropics .

Way of life, reproduction

Pair in amplexus ; the females are usually significantly larger than the males.
Roach tree frog spawning clumps on the underside of the leaf

Red-eyed tree frogs are nocturnal and spend the day high up in the trees, where they hide on the underside of large leaves and attach to sleep. At dusk they become active, descend and hunt for small invertebrates or, during the rainy season (May to November), devote themselves to courtship and reproduction. In addition, the males utter mating calls (a sharp, repeatedly repeated “chack” or “chack-chack”) near standing waters, which attract the females. In addition, they produce turf calls that sound like a laugh or warble to deter rivals. According to a new study, communication with other males also apparently includes body vibrations, which are used to set plants in motion. These so-called tremulations are interpreted as an aggressive signal with which competing males are to be driven out of the area of ​​their own courtship area.

If two different sexual partners meet, the male clasps the female from the back. The couple first go into the water for a few minutes in order to absorb liquid for the spawn through the skin. Finally it climbs high into the vegetation, where several clumps of spawning, each containing around 40 eggs, are stuck to leaves that are located above a suitable pool. Occasionally the leaf is folded in such a way that it better protects the spawn from solar radiation and predators. A female can produce several (up to five) spawning balls in one night, which consist of light green eggs in a clear gelatinous mass. Immediately after being laid, the eggs are inseminated by the sitting male.

After usually six to eight days of embryonic development, the tadpoles hatch and "drip" into the water below the spawning area. Larvae that land on other leaves or on the ground during this procedure are still able to survive for up to 20 hours and are ideally washed into the larval pool by the next rain. The hatching process of a spawning lump can take place synchronized within minutes or extend over several days. The embryos apparently also react to certain vibrations, such as those caused by tree snakes (e.g. Leptophis ahaetulla and Leptodeira annulata ), which are major predators of the spawn. In such a case, all embryos of a clutch can slide out of the jelly at the same time and thus escape the snake. The tadpoles, which are olive-green on top and initially have unusually large outer gills when hatched, grow to a length of around 48 millimeters in the pond and are quite robustly built. After about 80 days, they complete the metamorphosis into small tree frogs and climb ashore. They reach sexual maturity about two years later.

Hazard and protection

During nocturnal activity the greenish back color appears darker than during the day. Some specimens also have irregular white spots that can be slightly raised.

Due to its relatively large distribution area, the species Agalychnis callidryas is currently not considered endangered. In general, the red-eyed tree frog is called common, although the trend is in some cases downwards and the threat of local habitat loss is present. Several agalychnis species are negatively affected by the fungal disease chytridiomycosis . (The Mexican population of the species A. moreletii, for example, is said to be on the verge of extinction.) Red- eyed tree frogs are also in high demand as terrarium animals in the international pet trade. In the US alone in the last decade at least 221,000 were Agalychnis -Exemplare imported from Central American countries, where this is likely to represent only a fraction of the actual trade movements. So far, apart from national laws in the countries of origin, there have been no further import restrictions for wild-caught animals. At a species protection conference in Doha ( Qatar ) in March 2010, however, it was decided to include the entire genus Agalychnis in Appendix II of the Washington Convention on Species Protection (CITES). In the animal trade, this includes proof of export permits from the countries of origin.

swell

Individual evidence

  1. Distribution map for Agalychnis callidryas at www.iucnredlist.org
  2. Diercke World Atlas. 5th act. Edition. Westermann, Braunschweig 2002, ISBN 3-14-100600-8 , pp. 220-223.
  3. Michael S. Caldwell, Gregory R. Johnston, J. Gregory McDaniel & Karen M. Warkentin: Vibrational Signaling in the Agonistic Interactions of Red-Eyed Treefrogs. Current Biology, published online: May 20, 2010 ( doi: 10.1016 / j.cub.2010.03.069 )
  4. a b Overview of the "Species Survival Network" (PDF online; 112 kB)
  5. Press release of the Federal Environment Ministry on the results of the species protection conference in Doha ( Memento of the original of April 8, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.bmub.bund.de

literature

Web links

Commons : Red- eyed Tree Frog ( Agalychnis callidryas )  - Collection of images, videos and audio files