- 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.
- Author: Kathy Keatley Garvey
Her presentation, hosted by Emily Meineke, assistant professor of urban landscape entomology, begins at 4:10 on Wednesday, April 28. Access the one-hour seminar via this Zoom link.
In her abstract, Currano says: "Fossil leaves preserve the scars of insect-feeding damage, allowing paleontologists to investigate plant-insect interactions deep in Earth's past. My research on 21-million-year-old fossils from Ethiopia and 59-to-52- million-year-old fossils from Wyoming demonstrates that the diversity and intensity of insect feeding on leaves is affected by both climate and plant nitrogen concentration."
Currano, an associate professor of paleobotany, uses fossil plants to investigate the response of ancient forest ecosystems to environmental perturbations. "Specifically," she asks on her website, "how did environmental changes affect taxonomic diversity, ecosystem structure, plant-insect interactions, and biogeographic patterns? By understanding how ecosystems reacted to past changes, we can better predict how modern ecosystems will respond to anthropogenic changes like CO2-induced global warming. The research conducted in my lab is field-based, specimen-based, and collaborative."
Her current research focuses on 1) biotic response to climate changes during the hothouse Paleogene in the Western United States, particularly Wyoming, 2) the evolution of East African terrestrial ecosystems over the last 30 million years, and 3) the use of fossil plants to reconstruct paleoclimate and paleoenvironment.
Currano holds a bachelor of science degree (2003) from the University of Chicago and a doctorate (2008) from Pennsylvania State University.
Currano and Lexi Jamieson Marsh (founder and director of On Your Feet Entertainment) co-founded The Bearded Lady Project: Challenging the Face of Science, a documentary film and photography project that "investigates our stereotypes of what a field scientist looks like."
The mission of The Bearded Lady Project: Challenging the Face of Science, is twofold: "First, to celebrate the inspirational and adventurous women who choose to dedicate their lives in the search of clues to the history of life on earth," they write on their website. "And second, to educate the public on the inequities and prejudices that exist in the field of science, with special emphasis on the geosciences." Their documentary meshes art with science. They have also set up a scholarship fund to support future female paleontologists. (See paleosoc.org)
Cooperative Extension specialist Ian Grettenberger coordinates the weekly UC Davis Department of Entomology and Nematology seminars. For technical issues, he may be reached at imgrettenberger@ucdavis.edu