The answer, it seems, is that modular chunks of regulatory DNA that control the red colour "master gene" optix have been mixed and matched by mating between different species of butterfly, allowing complex combinations of red "dennis" patches (on forewings) and rays (on hindwings) to emerge in different species. A paper just published in PLOS Biology, for example, examines how the wing patterns of 17 species of Amazonian Heliconius butterflies have arisen. And because the benefits conferred by these depend in turn on the environment, location and other (equally evolvable) creatures such as predators or other butterflies, the forces underlying pattern evolution are complex, and the mechanisms by which they arise are fascinatingly elegant. But the nature, development and evolution of these staggeringly diverse decorations (of the more than 18,000 species of butterfly, almost all differ in their wing patterns) has also attracted the attention of scientists although studied since antiquity, many butterfly secrets continue to be revealed, as this selection of research published in PLOS journals and other open access sources in the last 12 months shows.īutterfly wing patterning seems to serve many functions related to survival – camouflage, mimicry, mate recognition or warning signals.