Purple butterflies evolved by scientists, according to Biology News Net 5 August 2014 and PNAS doi: 10.1073/pnas.1402770111. Scientists at Yale university have “produced the first structural colour change in an animal by influencing evolution”. Biology News Net quotes Antónia Monteiro, one of the researchers, described the experiment: “What we did was to imagine a new target colour for the wings of a butterfly, without any knowledge of whether this colour was achievable, and selected for it gradually using populations of live butterflies”.
In the PNAS summary the research team described their experiment: “We used artificial selection on a laboratory model butterfly, B. anynana, to evolve violet scales from UV brown scales and compared the mechanism of violet colour production with that of two other Bicyclus species, Bicyclus sambulos and medontias which have evolved violet/blue scales independently via natural selection”.
The colour of these butterfly wings is produced by reflected light from the scales on their wings, rather than from pigment. The purple colour is produced by the scales reflecting light at a wavelength of 400nm. Starting with brown butterflies, the scientists chose butterflies whose scales reflected light closest to 400nm and bred them together, repeating the process for successive generations until they got butterflies with a purple stripe on their wings. The scientists examined the scales of the newly bred purple butterflies and found the purple coloured regions had thicker scales than the original brown butterflies. They also examined the scales of a closely related butterfly species that was naturally purple, and found they also had thicker scales than brown ones.
The research team concluded: “This work shows that populations harbour large amounts of standing genetic variation that can lead to rapid evolution of scales’ structural colour via slight modifications to the scales’ physical dimensions”.
Editorail Comment: In spite of the boastful statement quoted by Biology News Net which included the word ‘evolution’ and implying the scientists got something completely new to evolve, their conclusion in the PNAS article is an admission that they did not produce anything new.
Furthermore, in spite of the claim they were able to “to evolve violet scales from UV brown scales” the process had nothing to do with evolution. What they actually did was select from the variation already present until they got what they wanted and which was a result they already knew was a possibility because closely related species of this butterfly already had purple coloured scales.
This experiment is a good reminder that selection, whether artificial or natural, is a real process in biology, but it never produces the evolution of one kind of creature into another. Different coloured butterflies with different thicknesses of scales on their wings already existed before anyone did this experiment. Selection simply brought out the built-in variation that already existed within this kind of butterfly – exactly what you would expect to get if they were created as fully functioning creatures according to their kinds, just as Genesis says. Don’t forget these experiments also show nothing about how light reflecting scales came into being in the first place. (Ref. Lepidoptera, structural colour)
Evidence News vol. 14 No. 15
3 September 2014
Creation Research Australia