Scientists Unravel Missing Clues on Glowing Beetles’ Evolutionary History Using 100 Million-Year-Old Amber | The Weather Channel – Articles from The…

Artistic reconstruction of Cretophengodes azari male and female in the undergrowth of a Cretaceous rainforest.

Nature hosts astonishingly diverse types of species, which have been continuously evolving for hundreds of millions of years. Among them, some of the most fascinating living creatures are bioluminescent insects, which hone the ability to shine an eerie light in the dark. But scientists agree that not much is known about these tiny creatures and there are several missing puzzles in their evolutionary history, including the origin of their glow.

Now, a fresh study might have solved this mystery by studying an exceptionally well-preserved fossil of light-producing beetles caught in an ancient piece of amber. The exceptionally well-persevered amber was excavated from northern Myanmar, which belongs to the Cretaceous period, roughly over 100 million years old. As per the study authors, the location had a lot of insects during that time.

Missing clues

Cretophengodes azari, a fossil light-producing beetle from Cretaceous Burmese amber (~100 million years old).

The study states that finding this fossil provides some missing clues about the property of bioluminescence among ancient glowing insects, specifically beetles. On record, there exists more than 3,500 species of bioluminescent beetles and are known to be the most diverse light-emitting terrestrial animals. The modern-day insectsfireflies, fire beetles, and glow-worm beetlesuse the light-emitting ability to ward off predators, and attract mates. All these insects are part of a superfamily known as Elateroidea.

"Elateroidea is one of the most heterogeneous groups of beetles and that has always been very difficult for entomologists to deal with, particularly because important anatomical innovations evolved many times independently in unrelated groups, explains Erik Tihelka.

This rank includes about 24,000 known species, while many of them are still not known to scientists and there is a wider knowledge gap around the evolution of bioluminescence in beetles. By bridging this gap, scientists are striving to understand how the beetles evolved. For this study, the authors examined the well-persevered amber belonging to the Cretaceous periodwhen dinosaurs thrived on land. Some of our current understanding of beetles is because of the recovered fossils from that period.

The team found a light organ nestled in the abdomen of the insect species known as Cretophengodes. This is regarded to be one of the oldest-known bioluminescent beetles, and therefore can give some insight into the early evolution of beetles.

"The newly discovered fossil, preserved with life-like fidelity in amber, represents an extinct relative of the fireflies and the living families Rhagophthalmidae and Phengodidae," said Yan-Da Li from the Nanjing Institute of Geology and Palaeontology (NIGP) and Peking University in China.

Emitting light as defence

The researchers estimate that most of the light-producing beetles have a soft and small body, which makes them impossible subjects for vigorous lab tests. However, this new fossil was completely intact. For this study, the researchers examined fossilized amber of an adult beetle.

Experts have hypothesized that the bioluminescence property initially evolved in the beetle's soft and vulnerable larvae, which acted as a defense system to keep off predators. The fossil indicates that by the Cretaceous period the light production started to occur in adults as well. There is also a possibility that the function may have been opted by the adults in order to search for mates.

The phenomenon of bioluminescence is widely known through fireflies. The modern-day fireflies emit eerie light through the process of chemical reaction in their body. This is mainly due to the presence of an enzyme luciferase, which catalyse compounds named luciferin, which in turn releases a lot of energy in the form of light.

The study was published in the journal Proceedings of the Royal Society B and can be accessed here.

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Scientists Unravel Missing Clues on Glowing Beetles' Evolutionary History Using 100 Million-Year-Old Amber | The Weather Channel - Articles from The...