The blue poison dart frog or blue poison arrow frog (Dendrobates tinctorius "azureus") is a poison dart frog found in the "forest islands" surrounded by the Sipaliwini Savanna in southern Suriname. Its indigenous Tiriyo name is okopipi. The name "azureus" comes from its azure blue color. While first described as a valid species and usually recognized as such in the past, recent authorities generally treat it as a morph of D. tinctorius, although a few treat it as a subspecies of D. tinctorius or continue to treat it as its own species. To what extent it differs from the blue D. tinctorius in southern Guyana, adjacent Pará (Brazil) and possibly far southwestern Suriname, is also a matter of dispute, and many herpetologists, as well as many people keeping poison dart frogs in captivity, have not distinguished these, with all commonly being identified as "azureus".

Description

thumb|left|D. tinctorius "azureus" frogs in captivity

The blue poison dart frog is a medium-sized poison dart frog that weighs about and grows to in snout–vent length. Females are larger and on average about half a centimetre longer than males, but males have larger toes. Its bright blue skin, usually darker around its limbs and stomach, serves as a warning to predators. The glands of poisonous alkaloids located in the skin serve as a defence mechanism to potential predators. The black spots are unique to each frog, enabling individuals to be identified. In addition to differing in color, blue poison dart frogs also tend to have a distinctive hunch-backed posture and a relatively smaller, more oval (less round) tympanum than in other variants of dyeing poison dart frog.

Poison

The blue poison dart frog primarily employs pumiliotoxins (PTXs) to dissuade predation. PTXs are potent neurotoxins that disrupt neural signalling by binding to and forcing open ion channels, functionally disabling signalling potential. They are not as potent as the batrachotoxins employed by other species of poison dart frog (such as the golden poison dart frog), but are still sufficiently poisonous to discourage predation. There is a species of snake, the Northern redbelly, or fire-bellied snake, that has developed a resistance to these compounds.

Like all similar species, the blue poison dart frog does not produce the poison that it excretes onto its skin. Instead, they collect the poisons they use from the insects they prey on, in what is known as "sequestration". When bred in captivity, they will not develop poison, unless fed a diet including insects with the toxic alkaloid compounds they use. In a similar vein, wild-caught poison dart frogs that are kept in captivity will become less poisonous over time. While they cannot produce toxic compounds, some species can alter the poisons they ingest to increase their toxicity. As a morph of the dyeing poison dart frog, blue poison dart frogs have this ability, being able to metabolise pumiliotoxin into allopumiliotoxin, a compound five times as potent.

Captive care

In captivity, like most captive dart frogs, they eat a staple diet of fruit flies, pinhead crickets, rice flour beetle larvae, isopods, and springtails.

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File:Blue Poison Dart Frog - Singapore Zoo.png|Blue Poison dart frog, Singapore ZOO

File:2009-03-29Dendrobates tinctorius azureus106.jpg|Blue poison dart frog

File:Dendrobates tinctorius, Blue poison dart frog.jpg|Blue poison dart frog, side view, London ZOO, UK

File:Dendrobates tinctorius - Blue poison dart frog.jpg|Blue poison dart frog, London ZOO, UK

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References

  • University of Michigan