Blue poison dart frogs are among 300 species of "poison dart," "poison arrow" or "dyeing poison frogs," whose skin excretes alkaloid poisons to deter predators. They are thought to get their poisons from their natural diet, as they gradually lose their toxicity after being fed a different diet in captivity. These poisons may hold promise as medications.
They're Not Always Blue
The blue poison dart frog (Dendrobates tinctorius azureus) was considered a distinct species under its own name until DNA testing found it was a color variation of Dendrobates tinctorius. Tinctorius also has several common names, like dyeing poison-dart frog, and variations within the species could include red and yellow markings, along with blue and black stripes instead of dots. The striking coloration is thought to be a warning to predators. Those who see in color recognize the blues, yellows and reds, and those who see only in black and white recognize the pattern of black dots or stripes.
Near Water, Not in It
Blue poison dart frogs are diurnal, meaning they're active during the day when prey insects are available. They live near water but they don't have webbed feet for swimming, so they seldom enter the water. Males call for females, who will fight to mate with them. When the eggs are fertilized, the male will guard them until they hatch, then the male and female carry the tadpoles on their backs to water. The female will also visit the tadpoles, to lay unfertilized eggs for the tadpoles to eat.
These frogs excrete several alkaloid poisons from glands in their skin in response to stress or pain. The exact type and composition of the frogs' poisons depends on the species and their diet, but pumiliotoxins occur in all species groups of Dendrobates. Two other examples of neurotoxins found in some species are allopumiliotoxin aPTX (+)-267A and decahydroquinoline. The frogs lose their toxicity if their diets don't include poisonous insects, so once in captivity, they gradually lose their poisons and become harmless.
Old and New Uses of the Poisons
The neurotoxic effects of the poison on the frog's skin serve as a defense against the frogs' potential predators. However, many toxins can also serve as medicines at different doses, and pharmaceutical researchers are exploring the possibilities of using versions of these toxins as pain killers and treatments for muscular disorders.
- Oakland Zoo: Blue Poison Dart Frog
- AmphibiaWeb: Dart-Poison Frogs
- ARKIVE: Dyeing Poison Frog
- US National Library of Medicine: Evidence for an Enantioselective Pumiliotoxin 7-Hydroxylase in Dendrobatid Poison Frogs of the Genus Dendrobates
- Animal Diversity Web: Green and Black Dart-poison Frog
- Applied Science and Analysis Newsletter: Dart Poison Frogs and Their Toxins
- Photo Credit Jupiterimages/Photos.com/Getty Images
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