Palaeontologists, including researchers from the Museum für Naturkunde Berlin (MfN), has 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 infestation in fossil plants is spectacular and can be described as the oldest insect infestation in the history of the Earth. The finds, which are housed in the collection of the MfN, among others, show that this highly specialised behaviour 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.