Fossilized Wings Shed Light on Butterfly Evolution

Scientists have determined the coloration of a 200-million-year-old insect, a new study published in Science Advances reports. In the research, a group of international scientists successfully determined the color of an ancient butterfly wing by looking at wavelength-selective scattering patterns. This is important because, unlike pigments, structural colors are not easy to identify in ancient fossils.

To get around that, the team in the study used advanced imaging techniques to reveal ultrastructures — the architecture of cells visible with magnification — on the fossil’s surface. From there, they used optical modeling to properly interpret the structural patterns and characterize the wing’s optical properties.

This new research is the earliest evidence of structural colors among insect fossils. In addition, it also shows that the Micropterigidae lineage — which is the most primitive form of the group that contains both moths and butterflies — used fused wing scales and layer scale patterns to produce structural color patterns millions of years ago. 

Though they cannot say for certain, the team believes the fossilized wings analyzed in the research would have shone with a range of metallic hues. That is in line with other Micropterigidae species. 

Not only does this study give researchers new insight into butterfly evolution, but it also provides evidence that suggests that moths and butterflies had diversified their color patterns much earlier than previously thought. That could then mean scientists need to reconsider current models and reanalyze the common beliefs about structural color evolution in lepidopterans.