Shining Light On Why Beetles Glow

The discovery of a a 99 million year old amber fossil from Myanmar offers insight into how and why beetles began to glow.

AsianScientist (Nov. 8, 2021) – Each year, around a million tourists travel to remote mangrove rivers and swamps in Southeast Asia and North America for one purpose: to see fireflies and their luminous lightshows. Fireflies are one of the many bioluminescent members of the Elateroidea superfamily that exhibit the fascinating ability to produce light and glow.

While the chemistry and physiology of bioluminescence in elateroids is now reasonably well documented, much less is known about exactly how or why the ability evolved in the first place.

Now, research by a team of scientists led by the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) has shed some light on the evolution of bioluminescence. Their study, published in Proceedings of the Royal Society B, reports the discovery of a new elateroid beetle family in an amber fossil from North Myanmar.

Although the specimen, an extinct firefly relative, is approximately 99 million years old, it has been preserved with lifelike fidelity thanks to its fossilization in amber. This stroke of luck has given the researchers the rare opportunity to study it in remarkable detail.

“Most light-producing beetles are soft-bodied and quite small, and so have a scant fossil record. However, this new fossil is exceptionally well-preserved, even the light organ on its abdomen is intact,” said Dr. Cai Chenyang, research fellow at the University of Bristol and associate professor at NIGPAS.

According to the researchers, the discovery of the light organ is proof that bioluminescent beetles have existed since the mid-Cretaceous period, and this timing coincides with the time major insect-eating animals like frogs and birds were beginning to flourish.

“We think that light production initially evolved in the beetle’s soft and vulnerable larvae as a defensive mechanism to ward off predators,” said Palacký University Associate Professor Robin Kundrata, an expert on elateroid beetles. “It was later taken up by the adults as well and co-opted to serve other functions such as locating mates.”

Besides the insights it provides into the evolution of bioluminescent, the discovery adds a key branch to the elateroid tree of life.

The article can be found at: Li et al. (2021) Cretophengodidae, a New Cretaceous Beetle Family, Sheds Light on the Evolution of Bioluminescence.


Source: Chinese Academy of Sciences; Photo: Yang Dinghua.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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