Tomato plants can detect an imminent animal attack

Tomato plants can detect the telltale sign of nearby snails -- slime -- and release an enzyme that deters those and other pests before they even touch the leaves, according to new research. The defense mechanism also keeps caterpillars from munching on the plants. From Scientific American:

"None of the plants were ever actually attacked," says University of Wisconsin-Madison ecologist John Orrock. "We just gave them cues that suggested an attack was coming, and that was enough to trigger big changes in their chemistry..."

The research was comprehensive, (adds UC Davis plant communications expert Richard Karban who was not involved in the study), but he wonders how the tomato plants detected chemicals in snail slime that never actually touched them.

"That's the million-dollar question," Orrock says. He hopes future research will tease out the mechanisms that enable plants to perceive these relatively distant cues.

"That's the million-dollar question," Orrock says. He hopes future research will tease out the mechanisms that enable plants to perceive these relatively distant cues.