Mutant

The common blue butterfly always stands out in the field and is like a strong magnet for me and my camera. This particular example was glowing so brightly in the dried vegetation that I chased it from flower to flower to catch a photo. It was only when I downloaded the photos that I noted that it had a mutation in the wing colour! In addition, the costal margin of the "mutated" hindwing is positioned differently compared to the wild type wing.
Looking up research on butterfly wing pattern I came across recent research by scientists at the Smithsonian Tropical Research Institute. They used reverse genetic engineering to modify a gene called WntA (previously identified as a important player in butterfly wing pattern. Beside revealing incredible change in pattern upon the mutations.. "In Heliconius butterflies, what was a red stripe in wild butterflies became a large red spill i moved. Mutant monarch butterflies grew white scales along the edges of their wings"
..their research also revealed something very unexpected. I know this is going to be a long post, but I'll quote directly the scientists for more clearness:

"There's a popular misconception that, during metamorphosis, the entire caterpillar liquefies in its cocoon. And then this larval smoothie congeals into a butterfly. But that's not how it works, Martin said. Some of the animal's body parts begin growing as caterpillars and stay intact through the metamorphosis process.

In fact, the study authors found, WntA turns on while the animals are caterpillars. WntA, a signaling gene, begins coordinating specific parts of the wing pattern even before the limbs are visible.

“In the larva you have miniature baby wings that are growing trapped inside the body,” Martin said. “We were blown away to see that the WntA gene was already providing the spatial information necessary to make patterns.”

When the butterflies reached adulthood, WntA's flexibility came into focus. It had switched from penciler to inker to painter and back again, its purpose written and rewritten over millions of years of evolution, persisting across butterfly species."

I find this terribly fascinating.

For the original article: https://www.pnas.org/content/114/40/10701