Strawberry Poison Dart Frog

Oophaga pumilio

(previously refered to as Dendrobates pumilio)
Family: Dendrobatidae
Order: Anura
Class: Amphibia
Phylum: Chordata
Kingdom: Animalia


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Range and habitat: The O. pumilio is found throughout Central America. It is highly common throughout the range of eastern central Nicaragua, through Costa Rica and northwestern Panama. The frog is also found in Chocoan Colombia, and parts of western Ecuador. Due to its high activity during the day and great population density, it is well recognized.It is commonly found in lowland and premontane forests. Due to the heat and lower humidity of the lowlands, most species remain active only in the morning and evening, or during rainy periods. They live in undisturbed areas or abandoned clearings and may also inhabit cacao plantations. The frogs tend to live in trees, under leaves, logs and rocks on the forest floor.
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Coloration: The strawberry poison dart frog is famous for its widespread variation in coloration. The variety is though to range between fifteen to thirty color morphs. The most common color pattern throughout the species' range is a red body with the upper surfaces of the hind limbs blue, purple, or black. The ventral color may be yellow, red, white or blue. In addition the body may be unicolored, spotted, or speckled. This morph is often described as "blue jeans" coloration pattern. Its coloration is a characteristic of aposematic, though the intensity of the color is not reflective of its toxicity. Its bright coloration is used to warm predators that they are unprofitable prey. The steroidal alkaloid toxins which reside in its skin are highly poisonous and affect nerve and muscle activity.

Morphology: The morphology of frogs is unique among amphibians. Compared with the other two groups of amphibians frogs are unusual because they lack tails as adults and their legs are more suited to jumping than walking. Their long hind legs and elongated ankle bones allow them to jump very well. They have a short vertebral column, with no more than ten free vertebrae, followed by a fused tailbone, resulting in a tailless phenotype.


Behavior: Oophaga pumilio is known also known for its extensive dual parental care. The males defend and water the nests while the females feed
the tadpoles their unfertilized eggs. Males can often be heard calling persistently throughout the day, and sometimes during the night when the moon is full, in attempts at attracting potential mates. Their insect like call of “buzz-buzz-buzz,” doesn’t seem to be deterred even when it is raining heavily, so if nothing else, the male is quite relentless in its courtship. The female will then approach a male and the male will lead the way to a suitable egg-laying site. Females invest more heavily in terms of energy expenditure, time investment and loss of potential reproduction. They provide energetically costly unfertilized eggs to the tadpoles until metamorphosis. It takes around seven to ten days for the eggs to hatch and meanwhile, the males carry out the task of hydrating th
e eggs, by carrying water in his cloaca, on a daily basis. Once the eggs hatch, the females carry each tadpole to different locations, usually filled with water. Th

e parental care of poison frogs is usually over, yet this is the time in which the strawberry poison dart frog separates itself. The female regularly visits each location and deposits unfertilized eggs for feeding the tadpole. It takes around 30 to 45 days for the tadpoles to metamorphose into froglets. During this time the female remains sexually inactive, where as the males remain sexually active throughout the rearing process. The tadpoles are scattered around the habitat to increase the odds of survival. This is necessary because the tadpoles lack the toxic substances used for defense by the mature adult frogs.

As a result of this necessity for plenty of space to separate their offspring, poison frogs are very territorial. Males are extremely territorial, guarding small areas of land. When provoked will jump on top of an interloping male, wrestling for up to 20 minutes.
Both frogs stand on their hind legs and try to push one another to the ground with their front legs. Once one is pinned, the victor, usually the inhabitant of the territory, allows the other to leave. These behavioral tendencies demonstrate the intelligence of the frogs, as they have adapted the common frog's behavior to ensure the survival of their unique species.

Aposematic prey are thought to move slowly and openly near predators, but exhibit reduced escape behavior. Oophaga pumilio changed directions less when approached than not; many exhibited no escape behavior. Aposematic species move slowly near predators, but retain risk-assessment mechanisms due to occasional predation. Differences in escape between poison dart frogs and frogs with no poison frogs suggest that dendrobatid defensive behavior may have been molded to maximize the effectiveness of aposematism.


Diet: O. pumilio has a specialized diet of small arthropods. Poison dart frogs feed mostly on spiders and small insects such as ants and termites, which they find on the forest floor using their excellent vision. They capture their prey by using their long sticky tongues. Ants and mites comprise 90% of the frog’s diet. The alkaloids in the ants of their diet contribute to, but do not determine, the frog’s degree of toxicity. The frogs genus Oophaga means "egg eater." As a tadpole the frog consumes unfertilized eggs dropped by their mother as their primary diet.

Ecology and interactions with other species: Because of their poison, O. pumilio does not have many predators. As eggs, this species is preyed upon by fungi, worms, snakes, and even other frogs.

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The only natural predator of most poison dart frogs is a snake called Leimadophis epinephelus, which has developed a resistance to the frogs' poison

Humans have taken advantage of their attractive coloration. They are commonly kept as household pets and are found in zoos across the country. They have been imported in vast quantities to the United States and Europe since the early 1990s, when they would typically be found for around $30 each. These shipments have since stopped, and poison dart frogs are much less common and available in reduced diversity. Smuggling of dart frogs is less common elsewhere, but still problematic as it kills large numbers of animals and frequently degrades or destroys viable habitat.

It has been proposed that there is a symbiotic relationship between Ophaga pumilio and the mites that they eat. As mentioned previously, the frogs obtain some of their poison from their diet and therefor rely on other species to obtain their defense mechanism. The exact specification of the interaction have not specifically been defined yet.
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An oophaga in its natural leaf litter environment


Personal Experience: The Ophaga pumilio was found abundantly through out Costa Rica. It was common in the rainforest and still found when close to the coast line. The males are active all year round, calling for females. The mating call becomes background music to the forest. They were much more active during periods of rain, though they were not deterred from drier days. The male calls out for the females, and the female walks toward the sound she selects. Some times a second male will hide near by another male and steal the female as she approaches the calling mate. It has been proposed by some researchers that the frogs can change their color slightly depending on the temperature or even the mood of the frog (though this has not been proven).




References:
http://en.wikipedia.org/wiki/Strawberry_Poison-dart_Frog
http://www.nature.org/animals/amphibians/animals/poisondartfrog.html
http://en.wikipedia.org/wiki/Poison_dart_frog
http://www.tropical-rainforest-animals.com/Strawberry-Poison-Dart-Frog.html
Saporito, Ralph A. Spatial and temporal patterns of alkaloid variation in the poison frog Oophaga pumilio in Costa Rica and Panama over 30 year
s.
Cooper, William E.; Caldwell, Janalee P; Vitt, Laurie J. Conspicuousness and vestigial escape behaviour by two dendrobatid frogs, Dendrobates auratus and Oophaga pumilio