Insects Are Causing Record Levels of Plant Damage as Insect Populations Drop

New research compares insect herbivore damage to modern-era plants to that of ancient leaves dating back roughly 67 million years.

Unprecedented levels of insects damaging plants

(Photo : Jake Gard/Unsplash)

The study is the first of its type, comparing insect herbivore damage to modern-era plants with that of preserved leaves dating back to the Late Cretaceous period, about 67 million years ago, as per ScienceDaily.

The research was published in the journal Proceedings of the National Academy of Sciences.

According to the lead researcher, UW Ph.D. graduate Lauren Azevedo-Schmidt, now a postdoctoral research associate at the University of Maine, their 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 disparity between present and fossilized insect damage is startling.

Azevedo-Schmidt collaborated on the study with UW Department of Botany and Department of Geology and Geophysics Professor Ellen Currano and University of California-Davis Assistant Professor Emily Meineke.

The researchers compared fossilized leaves with insect feeding damage from the Late Cretaceous to the Pleistocene epochs, around 2 million years ago, to leaves gathered by Azevedo-Schmidt from three current kinds of wood.

The thorough study examined many forms of insect damage, discovering significant increases in all contemporary damage compared to the fossil record.

According to the researchers, data show that plants in the present era are experiencing record levels of insect damage, despite global insect decreases, and that the gap may be explained by human activity.

More study is needed to pinpoint the specific causes of increased insect damage to plants, although experts believed that a rising climate, urbanization, and the introduction of exotic species have all had a role.

"We hypothesize that humans have influenced (insect) damage frequencies and diversities within modern forests," the researchers wrote, with the most human impact occurring after the Industrial Revolution.

By this hypothesis, herbarium specimens from the early 2000s were 23 percent more likely to have pest infestations than samples obtained in the early 1900s, a pattern that has been linked to climate warming.

However, they claimed that climate change does not entirely explain the rise in insect damage.

According to the researchers, the extent of human effect on plant-insect interactions is determined not just by climate change but also by how humans interact with the terrestrial landscape.

Also Read: Gene-edited Crops Helps the World To Ensure People's Food Security

Plant Defense against Herbivorous Pests

Plant-insect herbivore interactions are major factors of plant production in both managed and wild vegetation, as per Frontiers.

Plants have evolved a variety of defenses in response to assault to limit the risk of harm and loss of output. Crop losses due to arthropod pest damage might surpass 15% per year.

Crop domestication and selection for increased yield and quality can modify the crop's defensive capacity, increasing dependency on synthetic crop protection.

Sustainable agriculture, on the other hand, is dependent on lower chemical inputs.

As a result, there is an urgent need to uncover plant defense features for crop enhancement. Resistance and tolerance strategies are two types of plant defense.

Plant features that confer herbivore resistance often prevent or minimize herbivore damage by expressing traits that discourage pests from settling, clinging to surfaces, feeding and reproducing, or decreasing palatability.

Plant herbivory tolerance entails the development of characteristics that reduce the detrimental impact of herbivore damage on productivity and output.

Understanding the underlying defense processes and identifying the defensive qualities produced by plants to dissuade herbivores or reduce herbivore damage is critical for agricultural scientists to harness plant defensive traits in crop development.

Researchers analyzed the features and processes behind herbivore resistance and tolerance in this review and find that physical defensive traits, plant vigor, and herbivore-induced plant volatiles, as well as mixed-species crops, have significant use in pest management.

Furthermore, they highlighted developing ways for expediting the identification of plant defensive features and easing their implementation to improve crop protection's future sustainability.