BUTTERFLIES in Central America are providing evidence for inter-species breeding as an evolutionary force. Contrary to existing theories, the resulting hybrids can be highly fertile and viable, a study of two members of the Heliconius genus suggests.
James Mallet, an evolutionary biologist at University College London, set out to study the flow of genes between the two genetically and physically distinct butterfly species Heliconius cydno and H. melpomene (see below) whose ranges overlap in Panama. H. cydno, which is found mainly to the north, is coloured black, white and blue, sometimes with iridescent yellow markings. This pattern mimics other…
