Pigmentation in butterfly wings

The colours on butterfly wings are used as an advertisement. The patterns on the wings enable butterflies to recognize their own species at a distance and differentiate between males and females – rather handy when you’re hunting for a partner. Just like a pointillist painting, the surface of the wing is constructed of a huge collection of coloured dots, called scales, each about 50 x 250 micrometers in size.

However, scientists don’t yet know very much about how the colour on the wings is formed. What they do know is that the colours are created in two different ways: via pigments and via nanostructures on the scales, which ensure that light is distributed in ways that are sometimes spectacular. These so-called structure colours can clearly be seen on the morpho butterflies of the South American rainforests.

Cabbage white
Marco Giraldo examined the structure and the pigments of the wings of the cabbage white and other Whites from the Pieridae family. The physicist chose the Whites because they have relatively simple pigmentation. By comparing the scales of various sorts under an electron microscope, he discovered how the colouration of Whites is caused. Giraldo is the first to clarify how the colour of these butterflies is influenced by the nanostructural characteristics.
Scale structure
Although the spatial structure of a scale depends on the type of butterfly, there are a number of general characteristics: A scale consists of two layers, linked by pillars. The undersurface is virtually smooth and without structure, but the upper surface is formed by a large number of elongated, parallel ridges, about one to two micrometers from each other. The colour is determined by the dispersal of light by the scale structures and by the absorption of light by any pigments present. The pigments of the cabbage white, for example, absorb ultraviolet light and the brimstone blue light. At the same time they also scatter white or yellow light respectively.
Effective
Giraldo also discovered that the wings of Whites are constructed in a surprisingly effective way. Both sides of the wings have two layers of overlapping scales that reflect light. The more scales there are, the more light is reflected. This light reflection is very important as butterflies want to be seen. Giraldo discovered that these two layers form an optimal construction: with more than two layers the reflection may be improved, but the wing would become disproportionately heavy.
Japanese males
Giraldo has also discovered why Japanese male cabbage whites are better at recognizing females than European cabbage whites, who still make mistakes in this area. This is because the wings of Japanese male and female cabbage whites differ subtly, unlike those of their European relatives: the scales on the wings of Japanese female cabbage whites lack specific pigment grains, those that ensure that UV light is absorbed. Males do have these pigment grains, as do both sexes of the European cabbage whites. This difference makes it easier for Japanese male cabbage whites, who unlike humans can see UV light, to differentiate between males and females.
Colour industry
New colour methods can be developed using the knowledge derived from Giraldo’s research. It may be possible to apply the nanostructures observed in butterflies to create impressive optic effects in paint, varnish, cosmetics, packaging materials and clothes. Industry is thus following butterfly wing research with great interest.

Media Contact

Communication Office alfa

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

Enhancing the workhorse

Artificial intelligence, hardware innovations boost confocal microscope’s performance. Since artificial intelligence pioneer Marvin Minsky patented the principle of confocal microscopy in 1957, it has become the workhorse standard in life…

In the quantum realm, not even time flows as you might expect

New study shows the boundary between time moving forward and backward may blur in quantum mechanics. A team of physicists at the Universities of Bristol, Vienna, the Balearic Islands and…

Hubble Spots a Swift Stellar Jet in Running Man Nebula

A jet from a newly formed star flares into the shining depths of reflection nebula NGC 1977 in this Hubble image. The jet (the orange object at the bottom center…

Partners & Sponsors