COLUMBUS, Mo., June 30 (UPI) -- Without caterpillars, there might not be any condiments -- naked hotdogs, dry salads, flavorless sandwiches.

The chemicals that give plants like mustard, horseradish and wasabi their pungent flavors are the result of the ongoing evolutionary chess match between leaf and caterpillar.


Over millions of years, a variety of plants developed the ability to produce glucosinolates as a defense mechanism against hungry caterpillars. But while the bitter chemicals prove poisonous to the hairy worms, they're quite delicious to the human tastebuds.

As researcher detailed in a new study on the subject, the first cocktail of glucosinolates didn't work for long. The caterpillars eventually developed a tolerance for the chemicals. So the plants pumped out more intense glucosinolates, with even more concentrated sharp-tasting flavors.

"We found the genetic evidence for an arms race between plants like mustards, cabbage and broccoli and insects like cabbage butterflies," study author Chris Pires, a professor of biological sciences at the University of Missouri, explained in a press release. "These plants duplicated their genome and those multiple copies of genes evolved new traits like these chemical defenses and then cabbage butterflies responded by evolving new ways to fight against them."

One of the most intriguing insights gleaned by Pires and his colleagues, is that the plants used duplication, as opposed to single mutations, to augment gene expression and facilitate new chemical defenses. It's this incessant genetic tweaking, through duplicated code, that accounts for the wide array of flavors produced by plants.

"Why do you think plants have spices or any flavor at all? It's not for us," Pires told NPR. "They have a function. All these flavors are evolution."

Eventually, Pires hopes all this research will pay off in the form of designer plants.

"If we can harness the power of genetics and determine what causes these copies of genes," Pire said, "we could produce plants that are more pest-resistant to insects that are co-evolving with them -- it could open different avenues for creating plants and food that are more efficiently grown."