We may be mesmerized by the glowing aura of the fireflies that gently light up a summer evening – but their flashing lights are not for us.
Instead, these bright bursts are a form of communication. Other insects also communicate and do so in a variety of ways – for example, by rubbing their wings together or vibrating their abdomen. Scientists believe that some even communicate using different dialects.
After researching a newly discovered insect fossil, this ability to communicate began millions of years ago.
Engraved into ancient rock, scientists believe they have identified the oldest and perhaps most unique form of insect communication. They published their results on Thursday in the journal Nature.
“We have an insect with a completely different ‘tool’ for communication – and much older,” said André Nel, co-author of the study, professor at the National Museum of Natural History in France, to Inverse.
It is around 310 million years old. It lived during a period of mammal-like reptiles and before the dinosaurs.
What’s new – The oldest example of wing-based communication between insects to date is from the Middle Permian and was found in southern France, says Nel. The Middle Permian marked the end of the Paleozoic Era about 251 to 299 million years ago.
A close-up of the wings of the newly discovered insect Theiatitan azari.Thomas Schubnel
Nel and colleagues also found their fossil in France – a locust-like insect from the Titanoptera order. They describe Titanoptera insects in the study as an “order of likely carnivorous ‘giant’ insects with wingspans greater than 12 inches.
This discovery in turn provides the “oldest record of wing communication in insects,” writes the study team. It is 50 million years older than the second oldest insect fossil, the Titanoptera, and dates from the Carboniferous Period.
The research team named the newly discovered insect Theiatitan azari and paid homage to the Greek goddess of light Theia. It’s a cheeky nod to one of the ways this ancient insect likely communicated with its swarm: through flashing lights.
But this is where it gets complicated – previous studies suggested that insects of the Titanoptera order used a “communication tool on their forewings,” similar to live crickets, according to Nel.
However, the results of this study call into question the previously accepted hypothesis.
This hypothesis is based on the assumption that both crickets and the ancient Titanoptera insects use something known as a “file” to communicate, which makes sounds when the insect’s forewings move against each other.
Nel and colleagues argue that their Titanoptera lacks this file, so it couldn’t make a sound like crickets. So how did Theiatitan azari communicate?
How They Made the Discovery – To solve this communication problem, the team turned to a unique part of the insect they’d learned about through their fossil discovery: the special, enlarged areas on the wings of Theiatitan azari.
An analysis of these broadened areas on the wings of the newly discovered insect led to two hypotheses about how the ancient insect communicated:
- By crepitation: the insect suddenly spreads its wings while in flight and makes sounds to communicate with other insects
- Through light communication: the insect repeatedly shines light towards predators or prey through reflections from its wings.
The study team argues that both hypotheses are compatible with each other and are likely ways that the ancient insect communicated with allies and enemies. This also suggests that “sound and / or light communication is a very old phenomenon,” the researchers write.
How did ancient insects use their wings to communicate? Scientists are trying to answer this question in a new study, Getty
Why It Matters – Understanding how ancient insects communicate can help us learn more about the prey they feed on and the predators they tried to escape from.
“This discovery shows how complex ecosystems were in the late Carboniferous, with enough predators to” force “some insects to develop complex communication strategies – either to escape predators or to enable communication between the sexes,” says Nel.
These results aren’t just for paleontologists, argues Nel, as they argue that they are relevant to our modern insect ecosystem. The fossil and its analysis reveal a striking resemblance between ancient creatures and modern insects – a resemblance previously unknown.
“We were surprised to find such ancient insects that could generate flashes of light – a character that occurs in several very ‘modern’ insect groups, but was previously unknown to the Paleozoic or Triassic insects,” says Nel.
What’s next – In future studies, the team plans to look for sensory receptors in Titanoptera’s eyes that can detect lightning signals, as well as specialized ear drum organs that were once able to detect fluctuations in air pressure.
The presence of these receptors and organs could help confirm the lightning and crepitation hypotheses.
Until then, we can enjoy the fact that we know a little more about how insects came to communicate – and eventually populate the planet.
abstract: Acoustic communication has been known in insects since the Mesozoic Era, but earlier evidence of this behavior is rare. Titanoptera, an ‘orthopteroid’ Perm Triassic order, is one of the few candidates for paleozoic intersex call interactions: some specimens had highly specialized widened zones on the forewings that are currently – despite inconclusive evidence – considered to be resonators of a stridulation apparatus. Here we argue that the stridulation apparatus hypothesis is unlikely because the Titanoptera lack a stridulation file on their bodies, legs, or wings. Instead, when comparing these broadened zones with similar structures in existing grasshoppers, flies, and fossil dragonflies, we find evidence that the Titanoptera used their wings to create flashes of light and / or crepitations. In addition, we describe the first carbon-containing (~ 310 million) Titanoptera, which has such specialized zones and thus corresponds to the oldest record of wing communication in insects. Whether these communication systems were used to attract sexual partners and / or escape predators remains to be established.
