Natural hybridization in heliconiine butterflies: the species boundary as a continuum Mallet, James ; Beltrán, Margarita ; Neukirchen, Walter ; Linares, Mauricio Abstract Publication: BMC Ecology and Evolution Pub Date: 2007 DOI: 10.1186/1471-2148-7-28 Bibcode: 2007BMCEE...7...28M