When two species become three

摘要

Species do not always arise by new branches forming on the family tree. Sometimes the branches merge, and two species hybridise to form a third. Such hybrid speciation has previously been reported in plants, but never conclusively in animals. Now a study of butterflies has revealed that a wild species of the brightly coloured Heliconius butterfly in South America arose via the merger of two related species. What's more, something resembling this species can be artificially created in the lab.