Ancient amber proves early insects were keen on high society

"Downton Abbey" has nothing on these ants and termites. Thanks to 100-million-year-old amber, we now have even earlier proof that insects have long known something about social class.

This piece of 100-million-year-old amber shows two ant species fighting at the time the tree sap enveloped them.

AMNH/D. Grimaldi and P. Barden

As anyone with even a passing acquaintance with an ant farm knows, some insects are clearly organized into a society, with certain types of critters taking on certain roles. Bees, ants and termites are the shining examples of insects with this characteristic, known as advanced sociality, or eusociality.

Scientists have long thought these insects organized themselves into their roles as early as 150 million years ago, but the only proof we had of specialized ants and termites dated from about 20 million to 17 million years ago. That has changed. Researchers from the American Museum of Natural History and the University of Kansas have gotten their hands on chunks of 100-million-year-old amber from Myanmar.

The amber contains six termite species, which broke down along different functionality or castes, proving insect specialization did indeed occur early. While not placing the behavior quite as far back as 150 million years ago in the late Jurassic period, it does firmly fix it in the Cretaceous, which lasted from 145.5 million to 65.5 million years ago.

Two of the species found in the amber represent new discoveries. One is known as Krishnatermes yoddha, which is made up of worker, reproductive and soldier termites. The other is named Gigantotermes rex because it contains one of the largest soldier termites ever found. The battle bug, which has scissor-like jaws, measures approximately an inch long, with half that distance comprising its head.

Also in the amber, the researchers found evidence of different ant castes, including worker ants of different species battling it out.

"The behavior of these fossil ants, frozen for 100 million years, resolves any ambiguity regarding sociality and diversity in the earliest ants," said co-author Phillip Barden in a statement. Barden is a recent graduate of the comparative biology doctoral program at the museum's Richard Gilder Graduate School

The museum and university published two papers in the journal Current Biology on Thursday detailing their work with the amber. One discusses the ant discovery while the other details the termite find and concludes "that among all social species, termites probably had the original societies."

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