NOVEL INSECT HERBIVORY FROM THE LATE CRETACEOUS OF WESTERN NORTH AMERICA

Insect damaged leaves provide valuable and abundant evidence for organisms interacting in deep time. Plant-insect associations have been a cornerstone of terrestrial ecosystems for over 400 million years, and the evolution of flowering plants during the Late Cretaceous was a particularly tumultuous chapter in their history. Insect feeding traces are reported for a newly described leaflet from the Kaiparowits Formation (76.6–74.5 Ma) in the Grand Staircase-Escalante National Monument in south-central Utah, USA. This Laramidian formation is well known for its extensive vertebrate and invertebrate fossil records, as well as a rich and diverse insect-damaged flora. We analyzed 1560 leaflets for evidence of insect mediated damage and found a total of 40 damage types across eight feeding guilds: hole feeding, margin feeding, surface feeding, skeletonization, leaf mining, piercing and sucking, galling, and oviposition. Intensity of herbivory, measured as the percentage of insect damaged leaflets and percentage of removed plant tissue (herbivory index), was moderate in comparison to other terminal Cretaceous plant hosts. This profile of insect damage is a first attempt to understand the diversity and intensity of insect herbivory in the Kaiparowits Formation.