Leaf miners identified as oldest insect plague in the history of Earth

Summary

Morphology of Asteronomus maeandriformis in Autunia conferta from Crock, Thuringian Forest Basin, Germany. Credit: Scientific Reports (2025). DOI: 10.1038/s41598-025-15413-x Paleontologists, including researchers from the Museum für Naturkunde Berlin (MfN), have described the oldest insect larval feeding tunnels inside leaves, also known as leaf mines, along with associated egg deposits, based on plant fossils. The frequency of leaf mine infestations in fossil plants is spectacular and can be described as the oldest insect infestation in the history of Earth. The findings, which are housed in the collection of the MfN, among others, show that this highly specialized behavior of insect larvae already existed 295 million years ago, around 40 million years earlier than previously assumed. This once again underlines the relevance of natural history collections. Whether you are a farmer, gardener or walker, you have probably noticed the intricate feeding tunnels made by insect larvae inside leaves, also known as leaf mines. Living inside plant tissue has many advantages, such as protection from predators, dehydration, and harmful environmental influences. In addition, the larvae have an almost inexhaustible supply of food at their disposal, like a pig in clover. Nowadays, leaf mines are produced exclusively by insects such as beetles, dipterans, wasps and butterflies, which undergo complete transformation (metamorphosis) and are therefore referred to as holometabolous insects. They are highly adaptable and, in the course of evolution, have developed slender, maggot-like larvae without body appendages that are optimally adapted to life inside plant tissue. Location and stratigraphy of the locality Crock in the Thuringian Forest Basin in central Germany. Credit: Scientific Reports (2025). DOI: 10.1038/s41598-025-15413-x Until now, it was unclear when this successful strategy emerged among insects. The oldest reliable evidence of leaf mines to date comes from the Triassic p...