We often come across colorful butterflies but not ones with metallic hues. To see one such creature, the Morpho butterflies, we need to travel to South or Central America. A recent study shows that these blue butterflies have the ability to refract light so much that they appear to glow; their ancestors also displayed similar wing colors, especially in gold and bronze hues.
An international team of researchers, including Tim Starkey from the University of Exeter, who were studying moths and butterflies, which habited the earth almost 200 million years ago, discovered new evidence of color in Mesozoic fossils -- which was surprising. What is more, they were metallic, iridescent colors -- like those in the Morpho butterflies.
The researchers observed that there were microscopic ridges and grooves in the insects' wing scales. These ridges are also seen in today's moths and scientists concluded these tiny features are photonic structures and are able to produce metallic bronze to golden color appearances in the insect wings, reported Eureka Alert.
A recent study of fossils shows that the wing scales were structured in a way that could produce color. "We didn't expect to find wing scales preserved, let alone microscopic structures that produce color. This tells us that color was an important driving force in shaping the evolution of wings even in the earliest ancestors of butterflies and moths," said paleontologists Dr. Maria McNamara, who is the co-author of the study.
The research is published in journal Science Advances, April 11, 2018.
In insects, such flashy effects are important for their behavior and ecological functions, reported the website.
This study is also unique as it proves that even impression fossils, i.e. wing prints, are capable of preserving the structure of scales in sufficient detail as compression fossils.
While Impression fossils are formed when objects leave an impression on semi-stiff clay, which hardens over time, Compression fossils are formed when the object actually remains in the fossil but in a highly compressed form.
This is not the first time that fossilized moths and butterflies are studied and subsequently revealed interesting details.
In a January 2018 article, BBC said scientists came across fossilized butterfly scales the size of a speck of dust inside ancient rock from Germany and the discovery pushed back the date for the origins of the Lepidoptera.
Lepidoptera is an order of insects that has 180,000 species of butterflies and moths.