Harlequin Poison Frog, Oophaga histrionica

The Harlequin Poison Frog (Oophaga histrionica) known also as the Harlequin Poison Dart Frog, is a species of poison dart frog with a native range from Western Ecuador to the El Choco region of Colombia. The frog is usually found on the ground of tropical rain forests, amongst fallen limbs or leaf litter.

O. histrionica, along with O. speciosa, produces cardiotoxins referred to as histrionicotoxins. These moderate to highly toxic compounds act as potent non-competitive antagonists of nicotinic acetylcholine receptors, binding to a regulatory site located on the delta subunit of the ion channel complex. They have some affinity for sodium and potassium channels as well, although they’re much less potent for these targets. The synthesis of histrionicotoxins and a variety of homologues is synthetically challenging and has been the subject of many different attempts.

This frog has a variety of color morphs, which differ from one valley to the next in its native range. The base color is a bright orange, with a webbing of black over the whole body. Of the color morphs, the base color may be of clear to dull orange, yellow, white, red, or blue. The web pattern varies from small lines to big lines or spotted, incomplete lines, or a completely black frog with just a few spots. The variety of color morphs can be found in surprisingly close proximity, with different colored populations on adjacent hillsides.

This frog larvae is a required egg-feeder. After a parent transports newly-hatched tadpoles to a tiny water reservoir, the mother then returns periodically and lays unfertilized eggs, which the tadpoles feed on until ready to metamorphose and exit the water.

This behavior of rearing makes harlequins among the most difficult poison dart frogs to raise in captivity. As a result, they’re not widely found on the domestic pet market, and those that are available may be illegally smuggled imports rather than legally-bred domestic animals. Dart frogs that are caught wild are often stressed, require more care, my also be toxic and dangerous to handle, and have a much higher fatality rate. A few domestically-bred animals are nevertheless available, and are highly sought-after in the pet trade.

Image Caption: Oophaga Histrionica. Credit: Mauricio Rivera Correa/Wikipedia (CC BY-SA 2.5)