Here’s how ancient fossils preserved in Amber reveal the actual color of insects that lived on Earth around 99 million years ago. Essentially, what we are looking at here is an ancient time capsule that preserved fragments of a world long gone.
A research team from the Nanjing Institute of Geology and Paleontology at the Chinese Academy of Sciences (NIGPAS) has revealed the secrets of true insect coloration from 99 million years ago.
Typically, the fine structural details necessary for color preservation are seldom preserved in the fossil record, making most fossil reconstructions rely on the imagination of the artists.
Colors offer many clues to the behavior and ecology of animals.
They serve to keep organisms safe from predators, at the right temperature, or attractive to potential mates.
So understanding the coloration of long-extinct animals can help us shed light on ecosystems in the deep geological past.
The study, published in Proceedings of the Royal Society B, offers a new perspective on the lives of insects that are often overlooked, which coexisted alongside dinosaurs in the Cretaceous rain forests.
The Amber originates from the Middle Cretaceous, approximately 99 million years old, and dates back to the golden age of dinosaurs. It is basically resin created by ancient coniferous trees that developed up in a rainforest environment.
Animals and plants trapped in the thick resin were preserved, some of them with real fidelity, revealed researchers.
The rare set of amber fossils includes cuckoo wasps with metallic colors of teal, yellowish-green, purple, blue, or green pigments on the head, thorax, abdomen, and legs.
“In terms of color, they are almost the same as cuckoo wasps that live today,” explained lead author Dr. Cai Chenyang.
The researchers also identified samples of blue and purple beetles and a dark green metallic soldier fly.
“We have seen thousands of fossils of Amber, but color preservation in these specimens is extraordinary, “said co-author of the study Professor Huang Diying.
The type of color preserved in amber fossils is called structural color. It is caused by the microscopic structure of the animal’s surface.
The surface nanostructure scatters light of particular wavelengths and creates very intense colors.
“This mechanism is responsible of many of the colors we use. Know about our daily life,” revealed Professor Pan Yanhong, also from NIGPAS, a specialist in pale color reconstruction.
To learn how and why color is stored in some amber fossils but not others, and if the colors seen in the fossils are the same as the insects wore over 99 million years ago, the researchers cut through the exoskeleton of the specimens.
Using electron microscopy, they were able to confirm that the colorful amber fossils have a well-preserved exoskeleton nanostructure that scatters light.
The unaffected nanostructure of colored insects suggested that the colors preserved in Amber may be the same as those in the Cretaceous.
In contrast, in fossils that do not retain color, the cuticular structures are badly damaged, which explains their brown-black appearance.