The Huck Institutes of the Life Sciences

A plant sniffs out danger to prepare defenses against a pesky insect

"It's become increasingly clear in recent years that plants are responsive to odors," said Dr. Mescher, "but previous examples of this are all plant-to-plant. For example, some plants have been shown to respond to the odor of insect-damaged neighbors by priming their own defenses. What's new about this is that it seems that plants may sometimes be able to smell the insects themselves."

The tall goldenrod plant's reaction also appears to make it less attractive to other insects that might feed on it.

In a field study, the researchers found that the female flies were significantly less likely to lay eggs on plants exposed to the male pheromone, and about four times more likely to lay eggs on plants in a control group that were not exposed to this odor cue.

And in both field and laboratory experiments, other herbivores such as beetles caused significantly less damage to plants exposed to the fly pheromone, compared to the control group.

"It would seem that the plant senses the odor of the fly," Dr. Mescher said. "Then, it primes its defenses so that it can respond faster to the threat."

About the researchers

Dr. Mescher

Mark Mescher is an assistant professor of entomology at Penn State, and a faculty member of the Huck Institutes' graduate programs in ecology and plant biology and graduate training program in microbial genomics.

Dr. Tooker

John Tooker is an assistant professor of entomology at Penn State, and a faculty member of the Huck Institutes' graduate program in ecology.

Dr. De Moraes

Consuelo De Moraes is a professor of entomology at Penn State, and a faculty member of the Huck Institutes' graduate programs in ecology and plant biology and graduate training program in microbial genomics.

Ms. Helms

Anjel Helms is a graduate student in the Huck Institutes' Ecology program, and is an advisee of Drs. Mescher and Tooker.