Tropical Heliconius butterflies are well known for the bright colour patterns on their wings. These striking colour patterns not only scare off predators -- the butterflies are poisonous and are distasteful to birds -- but are also important signals during mate selection. Evolutionary biologists have now exploited the diversity of warning patterns of various Heliconius species to investigate the genetic foundations of these preferences. In the process, the scientists identified a gene that is directly linked to evolutionary changes in a visually guided behavior.
