Phyllobates bicolor

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Geographic Range

Phyllobates bicolor inhabits the tropical rain forests of Central and South America. The Choco Indians report finding them most commonly in the Pacific River area of Western Colombia (National Aquarium in Baltimore, 1987).

Habitat

Phyllobates bicolor are inhabitants of the tropical rain forests. They live colonially on the forest floor, often near small streams. They do well in the moist, humid conditions that the rainforests provide. The temperature rarely falls below 80 degrees Fahrenheit and the minimal annual rainfall is about 80 inches. Some areas may recieve as much as 400 inches of rain per year. This constant warmth and rainfall keep the habitat of Phyllobates bicolor green all year long (National Aquarium of Baltimore, 1987).

Physical Description

Phyllobates bicolor is typically golden-yellow in color and has black flecks on its hind legs. However, the color pattern varies widely. All of the poison-dart frogs have very bright aposematic coloration. This is used as a defense mechanism to warm potential predators of there extreme toxicity. These skin toxins are produced by special poison glands which are scattered all over the animal's body (National Aquarium in Baltimore, 1987). Phyllobates bicolor has terminal discs on its digits that allow them to climb well in shrubs and up mossy tree trunks (Mattison, 1987). Unlike males of most frog species, which are smaller than the females, male poison-dart frogs are relatively the same size when compared to the females (Badger et al, 1995).

Development

Reproduction

Most populations of Phyllobates bicolor breed continuously througout the rainy season, some every other month or even more frequently. In order to attract a female, the male will sit on a leaf and call by trilling or buzzing. This may go on for several days. Once a female is attracted, the mating pair must find a suitable location to lay their eggs. In some species, the male will select a location for the eggs prior to obtaining a mate. They are usually laid in a moist place, such as, in the leaf litter, under rocks, or even on certain rain forest plants (National Aquarium in Baltimore, 1987). Phyllobates bicolor have external fertilization with the male fertilizing the eggs as the female deposits them. During amplexus, the male has to clasp his mate under her chin instead of around her waist due to the similarities in size between the males and females (Badger et al, 1995). The female lays from 4-30 eggs in a jelly-like mass, which keeps them moist. Then, they are usually gaurded by either parent until they are ready to hatch. At this point in their development, water is required. The attending parent will squat in the gelatinous mass and allow the young to wriggle up his/her legs and onto their back. The larvae may remain on the adult's back for a few minutes or for several hours. The young are firmly attached by a mucous secretion which is only broken down by the immersion in water (Mattison, 1987). The parent will take the tadpoles to a suitable body of water where they are able to continue their development. This may consist of a puddle in a tree hole or a water holding plant such as a bromelaid or the leaf axils of palms or aroids. It takes about 3 weeks for the tadpoles to complete metamorphosis. After this time, the young will return back to their natural arboreal or terrestrial habitat (Badger et al, 1995).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)

Behavior

Phyllobates bicolor is active during the day and are very lively foragers. They move in short hops and are rarely still for more than a second or two (Mattison, 1987). During breeding season, when the male Phyllobates bicolor is calling for his mate, if another male responds, the calling male will attempt to evict him from the area using aggressive force. They will engage in ritualized wrestling bouts with one another typically while on their hind legs (Badger et al, 1995).

Food Habits

Phyllobates bicolor is primarily carnivorous. Adults feed on ants, termites, tiny beetles, and other small leaf litter arthropods. They capture their prey using their long, sticky retractable tongue. The young tadpoles may eat each other if placed together in a small area, but mostly they feed on insect larvae, detritis, and on unfertilized eggs left by a visiting female (National Aquarium in Baltimore, 1987).

Economic Importance for Humans: Positive

Native peoples in Colombia collect brightly colored frogs and use their poisonous skin secretions to coat the ends of hunting arrows. This method, first reported by British naval captain, Charles Stuart Cochrane, is highly effective in hunting jaguars, monkeys, birds, and small game animals. These skin toxins are of great interest to medical researchers because of their remarkable potency. The batrachotoxins secreted by Phyllobates bicolor are especially valuable for medical science and the study of anesthetics, muscle relaxants, cardiac stimulants, and the control of rapid or irregular heartbeats (Badger et al, 1995).

Economic Importance for Humans: Negative

Scientists believe that the skin toxins of Phyllobates bicolor are so toxic that .0000004 ounces may be enough to kill a human being. Toxins from these frogs work quickly, attacking the nerves and muscles. Nerve cells can no longer transmit impulses and muscle cells remain in an activated, contracted state. The result is death by respiratory or muscular paralysis (Badger et al, 1995).

Conservation Status

The pet trade and the destruction of the tropical rain forests are leading to a decline in the Dendrobatids such as Phyllobates bicolor. When the rain forests disappear, so do the animals that inhabit it (National Aquarium in Baltimore, 1987). One of the most spellbinding exhibits of live poison-dart frogs frogs in the United States is located at the National Aquarium in Baltimore, Maryland. Herpetologists there have had success breeding as many as 20 species, but they have also encountered a potential problem. Poison-dart frogs that are born in captivity do not secrete skin toxins. Scientists aren't sure why, but they speculate that the absence of certain bacteria in the environment or perhaps something missing in their diet may be the reason (Badger et al, 1995). The rain forest exhibit at the National Aquarium exists to make the public aware of the diversity of life found within the rain forests throughout the world. Hopefully, this awareness will create a desire to help protect the habitat of species like Phyllobates bicolor (National Aquarium in Baltimore, 1987).

Contributors

Erika Olson (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

References

Badger, D., J. Netherton. 1987. Frogs. Minnesota: Voyageur Press.

Mattison, C. 1987. Frogs and Toads of the World. New York: Facts on File Inc..

National Aquarium in Baltimore, .. 1987. "Poison Dart Frog: Amazing Amphibians" (On-line). Accessed November 1, 1999 at http://www.aqua.org/animals/species/prpdfrog.htm.