According to new research led by scientists from the University of Wyoming, insects are currently harming plants at levels never before seen, despite an overall decline in insect populations.
In the first study of its kind, insect herbivore damage to plants in the present is compared to fossilized leaves that date back to the Late Cretaceous, or roughly 67 million years ago. Journal Proceedings of the National Academy of Sciences publishes the findings.
The lead researcher, UW Ph.D. alumna Lauren Azevedo-Schmidt, who is currently a postdoctoral research associate at the University of Maine, claims that “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.” “The striking difference in insects damage between the fossilized record and the modern era.”
The study was carried out by Azevedo-Schmidt, Ellen Currano, professor in the UW departments of botany and geology, and Emily Meineke, assistant professor at the University of California-Davis.
The leaves collected by Azevedo-Schmidt from three contemporary forests were compared to fossilized leaves with insect feeding damage from the Late Cretaceous through the Pleistocene era, roughly 2 million years ago. The extensive study examined various forms of insect-caused damage and discovered significant increases in all recent damage compared to the fossil record.
The scientists claim that despite widespread insect declines, “our results demonstrate that plants in the modern era are experiencing unprecedented levels of insects damage.” They hypothesize that human activity may be to blame for the discrepancy.
The precise causes of increased insects damage to plants require further study, but according to scientists, urbanization, a warming climate, and the introduction of invasive species are likely to have had a significant impact.
The majority of human influence, according to the researchers, occurred after the Industrial Revolution. “We hypothesize that humans have influenced (insect) damage frequencies and diversities within modern forests.” In line with this theory, early 2000s herbarium specimens were 23% more likely than early 1900s specimens to have insects damage, a pattern that has been connected to climate change.
However, they claim that the rise in insects damage is not entirely explained by climate change.
According to the researchers, “this research suggests that human interaction with the terrestrial landscape, rather than just climate change, controls the strength of human influence on plant-insect interactions.”
