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Insects Interacting with Plants Play Mighty Roles on Earth for Millennia

by Devin Reese -- Jan 24, 2018
Devin Reese, smiling

Devin is the lead digital science writer for the Q?rius website. She writes and gathers media for the Smithsonian Science How? webcast series,...

Ancient scorpionflies pollinating the primitive seed plants Caytonia, at left, and Alvinia, at right. Depiction by Mary Parrish, Smithsonian.
Ancient scorpionflies pollinating the primitive seed plants Caytonia, at left, and Alvinia, at right. Depiction by Mary Parrish, Smithsonian.

Some systems that sustain life on Earth have been operating for a really long time. Cycles of oxygen, water, and minerals all come to mind. But what about the green world of plants around us, and of their abundant associates, the insects? Insects and plants have been interacting on Earth for hundreds of millions of years in a complex array of relationships. While insects are physically small, their ecological roles on the planet are mighty and provide structure to the ecosystems we rely on.

If you take a walk outside, it is hard to overlook insects in action. Rifle through a plant, and you'll find a menagerie of insects looking for food. Some are making holes, scraping off plant tissues, and skeletonizing leaves. Others are piercing plants and sucking up sap, or making squiggly paths as they mine leaf tissues. Plants may also serve as nurseries for insect larvae; adult insects leave distinctive scars where they have inserted their eggs.  Some insects even co-opt developmental machinery of plants to make tumor-like galls that provide protection and food for the larvae.

Many insects are also pollinators, enabling plant reproduction while scoring a food reward.  Pollination is the foundation not only of natural ecosystems, but also of our food supply. Without insects, we would be hard-pressed to feed our burgeoning human populations on Earth. On the other hand, defending crops from insect herbivores is also part of agriculture. Insects have evolved a huge variety of adaptations for exploiting plant organs and tissues.Brown 5-pointed leaf with damage marks, on white background

Paleobiologists who study fossils for evidence of insect-plant interactions have traced damage marks on 385-million-year-old leaves to insect feeding. The fossil evidence points to pollination also having a long history on Earth – showing up an estimated 125-170 million years ago. Compare those ancient relationships to our mere 200,000 years of human history on Earth . 

Scientists like Smithsonian Paleobiologist Dr. Conrad Labandeira continue to gather evidence to understand the deep history of plant and insect relationships on Earth. Learn more about Conrad’s research in the "Smithsonian Science How" webcast video, Fossil Forensics: Plant and Insect Relationships. Conrad will take you on a journey through time. You can also get teaching resources to use with the webcast video.

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