Insects are delicate, soft-bodied animals whose remains are challenging to preserve. While wings are often fossilized, the bodies of insects, if present, are usually fragmented pieces of the original prehistoric creature. This makes it difficult for scientists to study them. Paleontologists rely on trace fossils, which are primarily found as imprints on fossilized plants, to learn about prehistoric insects.
“We have a rich fossil plant record,” said Richard J. Knecht, a Ph.D. candidate in the Department of Organismic and Evolutionary Biology at Harvard. “When it comes to understanding the evolution and behavior of insects in the distant past, trace fossils provide more information than body fossils. This is because plants and the traces left on them preserve exceptionally well. Unlike a body, a trace does not move over time and is always found where it was created.”
In a recent study published in New Phytologist, researchers led by Knecht describe an endophytic trace fossil discovered on a Carboniferous seed-fern leaf. This finding represents the earliest evidence of internal feeding, specifically leaf mining, within a leaf. The 312-million-year-old Carboniferous fossil suggests that leaf mining behavior originated approximately 70 million years earlier than previously believed.
“Of all the ways insects feed internally within plants—such as mining the insides of leaves, creating tumor-like galls, boring into wood, and invading seeds to consume embryonic tissues—mining has been the most enigmatic,” explained co-author Conrad C. Labandeira, Senior Research Geologist and Curator of Fossil Arthropods at the Smithsonian National Museum of Natural History.
“The earliest evidence of mining dates back to the Early Triassic, shortly after the significant end-Permian extinction event. However, galls, borings, and seed predation existed much earlier in the Paleozoic era. The delay in the appearance of mining behavior has been a mystery. I believe we now have an answer.”
2023-10-06 18:24:03
Post from phys.org