Poison-Dart Frogs: Nature's Touch-Me-Nots
The humid air lingers over the dense and lush foliage on the floor of a Suriname rainforest. Trees sway with the wind in diverse rhythmic patterns. Droplets of water form a small cascade as they descend from leaf to leaf. A huge fern collects the water and produces a tepid pool. The pool contains a kaleidoscope of vividly-colored frogs. At first glance, one would immediately begin to touch and investigate these frogs of the rainforest. But no, these aren't "normal" backyard tree frogs, but living poisons calculating their prey and ready for their next attack. They are known as poison-dart frogs: nature's touch-me-nots.
The frogs contain poison secreted from glands in their skin; just a touch could be fatal. These unique frogs, which many might find frightening, play a particular role in their ecosystem and environment: the rainforests of Latin America. Biodiversity flourishes in this part of the world, especially Central America, due to this area being the crossroads of animals and plants from two separate continents. This is why such animals as the poison-dart frog thrive and play an important role to all. Humans, plants, and animals alike depend on these neon-colored frogs, and their disappearance would be devastating. From developing new painkillers to the preservation of age-old cultural traditions in Columbia, the existence of these frogs allow humans to combat diseases and practice the hunting rituals initiated by our ancestors many centuries ago.
Plant ecologist Sir Arthur George Tansley developed the word "ecosystem" in 1935. Tansley defined the word as "a distinct unit of interacting organisms and their surrounding environment." Each ecosystem contains producers (plants), consumers (herbivores, carnivores, and omnivores), decomposers (fungi), and abiotic factors (non-living). Each category forms a specific trophic level, with each level being interconnected with the others. In order for a successful ecosystem to flourish, all trophic levels must be present and thriving in their habitat. Plants, the foundation of the ecosystem, form the first trophic level. Second, the primary consumer level, is the animal that feeds on the plant. Third, the secondary consumer level, is the animal that eats the primary consumer. Finally, the tertiary consumer level, is the animal that devours the secondary animal. The plant, or producer, collects its own energy from light which is passed down from animals consuming one another. The energy available for use by organisms at each trophic level averages only about 10 percent of the preceding level. The poison-dart frog's ecosystem contains all of these trophic levels within its environment of the rainforest.
There are three main roles these brilliantly colored frogs play in their own ecosystem. First, the poison-dart frog acts as a secondary consumer, feeding upon insects, worms, spiders, and centipedes. Spiders are often drawn to these colorful creatures, eyeing the frogs for a mid-day snack. When a spider takes a bite, it immediately starts foaming at the mouth. The poisonous toxins in the frog's vibrant skin kill the spider. The tables have turned; the frog is ready to enjoy its snack of the day, the spider. Due to poison-dart frogs being secondary consumers, they help limit the populations of the worms and centipedes. This prevents the ecosystem from having an over-abundance of these types of invertebrates. Second, as an animal, the frog releases carbon dioxide through respiration, thus aiding in the carbon cycle of the ecosystem. Through the carbon cycle, the ecosystem will recycle the carbon dioxide produced by animals and plants as they respire, and plants will use the carbon dioxide to perform photosynthesis. Hence, poison-dart frogs play an intricate part in supplying plants with carbon in order for the plants of the rainforests to produce food. Third, I believe that since poison-dart frogs eat insects, spiders, centipedes, and worms, these frogs could be introduced into various parts of the world and utilized as a defense against undesirable pests. The powerful toxins could easily kill unwanted and overpopulated insect territories. At the same time, children and other populations could just as easily be harmed by these poisonous frogs. If introduced into new regions of the world, poison-dart frogs would need to be monitored carefully.
Living in the ecosystems of Latin America is imperative for the survival of this species. Poison-dart frogs thrive in a moist environment with a high humidity level around 80 percent. Also, these frogs will find lukewarm pools of water located in the brims of leaves to lay their eggs and rear their young. These leaves are located high in the canopy making it less likely that other animals will eat them. Via this procedure, this species of the frog is capable of spanning numerous generations. Thus, the survival of Latin America's ecosystem and the poison-dart frog are interdepedent.
I believe that if the species of poison-dart frogs became extinct, humans would be most affected by the loss. Scientists are constantly using the environment around us to find cures for diseases. They are acknowledging the poison-dart frog's contributions. Many scientists are just now recognizing the importance of these frogs, which is why the loss of these animals would be detrimental to humans.
Deep within the Ecuadorian rainforests, one might find Epibpedobates tricolor, a poison-dart frog, lying on a palm frond near a babbling cascade. But this innocent looking creature secretes epibatidine, a chemical with anesthetic properties. A spider could be easily conquered with this secret weapon of the poison-dart frog, but scientists have found a beneficial way to use this potent chemical from Epibpedobates. Researchers at Abbott Laboratories developed a new painkiller from the chemical epibatidine, called ABT-594, after the National Institute of Health (NIH) isolated the poison from the Ecuadorian frog.
During the late 1970's the National Institute of Diabetes, Digestive, and Kidney Diseases discovered epibatidine blocks pain 200 times more effectively than morphine. Although scientists had tested the painkiller on rats, they feared it might be too toxic for human consumption. However, in the mid-1980's, scientists discovered the chemical structure of epibatidine through NHR spectroscopy and realized it was quite similar to nicotine. Nicotine attaches to nerve cells and creates an anesthetic effect. Abbott Laboratories then became involved in reading epibatidine. The researchers recognized the chemical structure of epibatidine was similar to an experimental drug for Alzheimer's disease. It was then that scientists started working on ABT-594. They got rid of the poisonous property of epibatidine that affected the cardiovascular and respiratory systems. AMT-594 will aid cancer victims who used morphine and experienced serious side effects from it. There are 30 million to 40 million Americans with moderate pain who do not respond well to painkillers but use them just to get through the day. Researchers say their quest for a new painkiller could be met by ABT-594.
Taking a sojourn to Panama, one will find Dendrobates auratus. This predator of spiders contains pumiliotoxin. Researchers claim this chemical might be used as a cardiac stimulant after heart attacks. The National Institute of Health states that poison-dart frogs offer over 300 alkaloid compounds. These chemicals are quite similar to cocaine and morphine, which again could assist other patients.
In addition, the poison-dart frog can be even more valuable in medical research laboratories. The frog's skeletal, muscular, digestive, nervous, and other systems are similar to those of more evolved animals. I believe that by inserting new chemicals, antibodies, and treatments into these frogs, scientists may see how more developed animals would react, since they have similar body systems.
Living through centuries of survival in the rainforests of Columbia, the Embera Choco people have depended on the existence of the poison-dart frog. Its loss would be culturally devastating to these native South Americans. The Embera Choco people are known around the world for their crafting of dart guns. Using the potent poisons secreted in the skin of Phyllobates terribilis, the natives rub dart tips in these chemicals. The tips made from the stems of palm trees are placed into a blowshaft. The Embera Choco then would lift the mouth of a long blowgun to their lips and give a swift blow. These potent darts are aimed at birds and other animals of the rainforests. This method of hunting for food, by using the toxins of poison-dart frogs on darts, has been passed down from generation to generation in the Embera Choco society. These natives enjoy the traditions of their ancestors, and the disappearance of these frogs would stifle their customs.
The relevance of the frog's poison ranges from the sophisticated scientific discoveries for medicinal use to the very primitive cultural significance, as when used by South American native tribes. I find it fascinating to realize the importance of the frog at two opposite ends of the spectrum in today's society.
Returning to the image of the tepid pool of water containing the kaleidoscope of multicolored frogs, one realizes the uniqueness these poison-dart frogs provide to the rainforests of Latin America. The world offers a vast amount of biodiversity, where each plant, animal, and microorganism has its own story to tell of its history, interactions, and survival. I am sure Sir Arthur George Tansley would agree the poison-dart frog is no less amazing. Its brilliant-colored skin tells its own peculiar story.
Associated Press. "Frog Poison Used in New Painkiller." Orlando Sentinel. January 2, 1998.
Biology. 783-789. Orlando: HBJ, Inc., 1989.
Microsoft Encarta '96 Encyclopedia. "Frog" and "Ecosystem" 1993-1995 U.S.A.: Microsoft Corporation.
Moffett, Mark. "Poison-Dart Frogs: Lurid and Lethal." National Geographic. 187(5): (May 1995) 98-111.Washington, DC: National Geographic Society.
Winchester, Jimmy. "Dendrobatid Frogs." http://pages.prodigy.com/bluefrog
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Less than 1 period.
Supplement a study of biology or biodiversity with an activity drawn from this winning student essay.
- Send students to this online article, or print copies of the essay for them to read.
- Have them write a brief essay that answers these questions: Do you think the author's idea of introducing poison-dart frogs into an environment as a defense against undesirable pests is a good one? Why or why not?
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