- Author: Kathy Keatley Garvey
Their work, “Insect Herbivory Within Modern Forests Is Greater than Fossil Localities,” appears in the Oct. 10th edition of the Proceedings of the National Academy of Sciences (PNAS). The first-of-its-kind study compares insect herbivore damage of modern-era plants with that of fossilized leaves dating as far back as 67 million years ago.
“Our work bridges the gap between those who use fossils to study plant-insect interactions over deep time and those who study such interactions in a modern context with fresh leaf material,” said lead researcher and ecologist Lauren Azevedo-Schmidt, formerly of the Department of Biology, University of Wyoming and now a postdoctoral research associate with the Climate Change Institute, University of Maine. “The difference in insect damage between the modern era and the fossilized record is striking.”
No stranger to UC Davis, Currano presented a UC Davis Department of Entomology and Nematology seminar, hosted by Meineke, on "Ancient Bug-Bitten Leaves Reveal the Impacts of Climate and Plant Nutrients on Insect Herbivores" on April 28, 2021.
“Plants and insects are the most diverse lineages on earth, but their interactions in the face of climate and other global changes are poorly understood…despite insect declines, insect damage to plants is elevated in the modern era compared with other time periods represented in the fossil record,” they wrote. “Plants today are experiencing unprecedented levels of insect herbivory, with unknown consequences for plant fitness and evolution.”
The scientists presented estimates for damage frequencies and diversities on fossil leaves from the Late Cretaceous (66.8 million years ago) through the Pleistocene (2.06 million years ago) and compared these estimates with recent (post-1955) leaves collected via paleobotanical methods from three modern ecosystems, including Harvest Forest, a 3000-acre ecological research area in managed by Harvard University and located in Petersham, Mass. The site, in operation since 1907, is one of North America's oldest managed forests.
Other ecosystems: the Smithsonian Environmental Research Center (SERC) of Chesapeake Bay, a 2,650-acre campus spanning forests, wetlands, marshes and 15 miles of protected shoreline, and the 3953-acre La Selva Research Station, Costa Rica, a private forest reserve.
The scientists advocate more research to determine the precise causes of increased insect damage to plants, but related that a “warming climate, urbanization and introduction of invasive species likely have had a major impact.”
“We hypothesize that humans have influenced (insect) damage frequencies and diversities within modern forests, with the most human impact occurring after the Industrial Revolution,” the researchers wrote. “Consistent with this hypothesis, herbarium specimens from the early 2000s were 23 percent more likely to have insect damage than specimens collected in the early 1900s, a pattern that has been linked to climate warming.”
“This research suggests that the strength of human influence on plant-insect interactions is not controlled by climate change alone but, rather, the way in which humans interact with the terrestrial landscape,” the researchers concluded.
Meineke, who joined the UC Davis faculty in 2020, served as a postdoctoral fellow at Harvard University Herbaria from 2016 to 2019, including a National Science Foundation-sponsored fellowship there in 2017. She holds a doctorate in entomology from North Carolina State University (2016), Raleigh, where she wrote her dissertation on “Understanding the Consequences of Urban Warming for Street Trees and Their Pests.”
Meineke helped spearhead the newly created Harvard Museum of Natural History's “In Search of Thoreau's Flowers: An Exploration of Change and Loss," hailed as an examination of the natural world and climate change at the intersections of science, art and history. The exhibit opened to the public May 14, 2022.