Toxicity of Panamanian Poison Frogs (Dendrobates): Some Biological and Chemical Aspects

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Science  19 May 1967:
Vol. 156, Issue 3777, pp. 970-973
DOI: 10.1126/science.156.3777.970


A small Neotropical frog, Dendrobates pumilio, undergoes interpopulational variation in color, degree of toxicity, size, and habits. Differences in body coloration encompass the visible spectrum from red to blue, as well as achromatic black and white. There are wide variations in the degree of toxicity, but these variations are not correlated with supposed warning colors. Extracts of skin yield two toxic compounds characterized as steroidal alkaloids with molecular formulae C19H33NO2 and Cl9H33NO3. The rapid rate of divergent evolution among populations of this frog may result from isolation and chance restriction of original heterozygosity, with subsequent selection acting on different and greatly limited mixtures of alleles.