Insect herbivory close to the Oligocene–Miocene transition — A quantitative analysis

Insects form an important part of modern terrestrial ecosystems, but while their body remains are rare in the fossil record, their trace fossils, such as feeding damage, are more common. Studies of insect herbivory on fossil leaves can provide key information for an ecological understanding of disturbance and biotic response in deep time, such as the response of insect damage frequency and diversity to changing vegetation and climate. In this contribution, I provide the first, high-resolution study documenting insect damage of fossil leaves that indicate the reaction of insect herbivores to changing regional climates and vegetation during the latest Paleogene in Europe. Insect damage censuses were conducted at six stratigraphic levels ranging in age from 27 to 23 Ma in the Siebengebirge area near Bonn, Germany. A total of 3122 fossil angiosperm leaves pertaining to 135 species were examined for the presence or absence of insect damage types (DTs); fifty-nine damage types were recorded. The most parsimonious explanation for the trends observed in this study is that the fossil insect damage represents a regional response to global environmental changes.