Poison Dart Frog

2 years ago by in Ecology, Ecology

animals-blue-poison-frog-slide1Poison Dart Frogs. They do not bite or sting anybody. Their poisons are the 250 times stronger than the  known most  effective poison. At the moment when you touch one of them, you will have a stroke.Their poisons can kill 30.000 mice.Their bodies are covered with poison.

Poison dart frog is the common name of a group of frogs in the family Dendrobatidae which are native to Central and South America. These species are diurnal and often have brightly colored bodies. Although all wild dendrobatids are at least somewhat toxic, levels of toxicity vary considerably from one species to the next and from one population to another. Many species are threatened. These amphibians are often called “dart frogs” due to the Amerindians’ indigenous use of their toxic secretions to poison the tips of blowdarts. However, of over 175 species, only four have been documented as being used for this purpose , all of which come from thePhyllobates genus, which is characterized by the relatively large size and high levels of toxicity of its members.

Most species of poison dart frogs are small, sometimes less than 1.5 cm in adult length, although a few grow up to 6 cm  in length. Most poison dart frogs are brightly colored, displaying aposematic patterns to warn potential predators. Their bright coloration is associated with their toxicity and levels of alkaloids. Frogs such as theDendrobates genus have high levels of alkaloids, whereas the Colostethus species are cryptically colored and are not toxic.

Poison dart frogs are an example of an aposematic organism. Their bright coloration advertises unpalatability to potential predators. Aposematism is currently thought to have originated at least four times within the poison dart family according to phylogenetic trees, and dendrobatid frogs have since undergone dramatic divergences – both interspecific and intraspecific – in their aposematic coloration. This is surprising given the frequency-dependent nature of this type of defense mechanism.

Adult frogs lay their eggs in moist places, including on leaves, in plants, among exposed roots, and elsewhere. Once the eggs hatch, the adult piggybacks the tadpoles, one at a time, to suitable water, either a pool, or the water gathered in the throat of bromeliads or other plants. The tadpoles remain there until they metamorphose, fed by unfertilised eggs laid at regular intervals by the mother.

Poison dart frogs are endemic to humid, tropical environments of Central and South America. These frogs are generally found in tropical rainforests, including in Bolivia, Costa Rica, Brazil, Colombia, Ecuador, Venezuela, Suriname, French Guiana, Peru, Panama,Guyana, Nicaragua, and Hawaii.

Many species of poison dart frogs are dedicated parents. Many poison dart frogs in the Oophaga and Ranitomeya genera carry their newly hatched tadpoles into the canopy. The tadpoles stick to the mucus on the backs of their parents. Once in the upper reaches of the rainforest trees, the parents deposit their young in the pools of water that accumulate in epiphytic plants, such as bromeliads. The tadpoles feed on invertebrates in their nursery, and their mother will even supplement their diet by depositing eggs into the water. Other poison frogs lay their eggs on the forest floor, hidden beneath the leaf litter. Poison frogs fertilize their eggs externally; the female lays a cluster of eggs and a male fertilizes them afterward, in the same manner as most fish. Poison frogs can often be observed clutching each other, similar to the manner most frogs copulate. However, these demonstrations are actually territorial wrestling matches. Both males and females frequently engage in disputes over territory. A male will fight for the most prominent roosts from which to broadcast his mating call; females fight over desirable nests, and even invade the nests of other females to devour competitor’s eggs.

Some poison dart frogs species include a number of conspecific color morphs that emerged as recently as 6,000 years ago. Therefore, species such as Dendrobates tinctoriusOophaga pumilio, and O. granulifera can include color pattern morphs that can be interbred.Differing coloration has historically misidentified single species as separate, and there is still controversy among taxonomists overclassification.

Many poison dart frogs secrete lipophilic alkaloid toxins through their skin. Alkaloids in the skin glands of poison frogs serve as a chemical defense against predation, and they are therefore able to be active alongside potential predators during the day. About 28 structural classes of alkaloids are known in poison frogs.The most toxic of poison dart frog species is Phyllobates terribilis. It is argued that dart frogs do not synthesize their poisons, but sequester the chemicals from arthropod prey items, such as ants, centipedes and mites – the diet-toxicity hypothesis. Because of this, captive-bred animals do not possess significant levels of toxins as they are reared on diets that do not contain the alkaloids sequestered by wild populations. Nonetheless, the captive-bred frogs retain the ability to accumulate alkaloids when they are once again provided an alkaloid-containing diet. Despite the toxins used by some poison dart frogs, some predators have developed the ability to withstand them. One is the snake Leimadophis epinephelus, which has developed immunity to the poison.

Chemicals extracted from the skin of Epipedobates tricolor may be shown to have medicinal value. Scientists use this poison to make a painkiller.  One such chemical is a painkiller 200 times as potent as morphine, called epibatidine; however, the therapeutic dose is very close to the fatal dose.

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