Fig. 2From: Extensive range overlap between heliconiine sister species: evidence for sympatric speciation in butterflies?Histograms of range overlap for heliconiine butterflies and birds. a diagnostic phylogenetic species (PSC), (subspecies used as a surrogate for PSC species), b relaxed biological species (BSC) sister species, c strict BSC sister species. For comparison, in d we show range overlap for sister species of birds [16]Back to article page