By Susan Milius
A South American butterfly has a checkered past, say biologists. It’s one of the few animal species that seems to have arisen via a supposedly rare path: crossing two older species.
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A black butterfly flashing bold stripes, Heliconius heurippa, came from the natural mixing of two other Heliconius species, says Jesús Mavárez of the Smithsonian Tropical Research Institute in Panama.