Moths and butterflies are far older than we thought, having evolved at least 200 million years ago. This means that while we often think of butterflies as being synonymous with flowers, the insects were actually fluttering around the world’s forests tens of millions of years before flowers even existed.
The evidence comes in the form of tiny fossil wing scales discovered in a drilled core from northern Germany. The scales, which show a variety of different shapes and forms, were found in a layer that dates to the late Triassic, putting them at around 200 million years old. This means that the fossil history of Lepidoptera has now been pushed back by a staggering 70 million years.
The work, published in Science Advances, also finds an amazing similarity between some of the fossil scales discovered and those that are found on a living group of moths known as Glossata. This is interesting because the group of moths and butterflies that contain sucking mouthparts, known as a proboscis, are nestled within Glossata.
This discovery therefore implies that the evolutionary origin of the proboscis, which is used by moths and butterflies within Glossata to suck nectar from flowers, is much more ancient than flowers themselves. But when the fossil ancestors of these recently discovered insects were first taking to the skies, flowering plants – known technically as angiosperms – were yet to exist.
“[Lepidoptera] likely evolved during the Triassic, and especially during the second half of the Triassic when climates were probably hot and dry,” explains Bas van de Schootbrugge, co-author of the study, to IFLScience. “So we think the adaptation to develop mouthparts to suck fluids – the butterfly “tongue” – was driven by their need to maintain fluids.”
At this time, the planet was dominated by gymnosperms, such as conifers, cycads, and ginkgo trees. The researchers suspect that the mouthparts on these early insects were then co-opted to suck up the sugary droplets produced by many of these plant species as they were now able to exploit this new resource.
Once the angiosperms started to become the dominant form of vegetation around 120 million years ago, the butterflies and moths were well-equipped to switch food sources.
This is backed up by the molecular evidence. “Based on the molecular clocks, Lepidoptera [had already] split from their sister group Trichoptera (caddisflies) during the Triassic, perhaps after the end-Permian extinction,” says van de Schootbrugge.
It is likely that after the extinction event at the end of the Triassic, in which insects largely managed to survive unscathed, the newly evolved butterflies and moths then radiated further.