By monitoring surface electrodes, biologists from the Universität Würzburg in Germany uncovered how Venus flytraps capture and consume prey using their prey-decomposing cocktail of enzymes.
“The Venus flytrap can count how often it has been touched by an insect visiting its capture organ in order to trap and consume the animal prey,” said Dr. Rainer Hedrich, lead-author of a study published in the journal Current Biology.
It’s well known that only two touches are sufficient to have a Venus flytrap close its trap. Scientists confirmed this by monitoring electrical activity using surface electrode measurements.
“In order to investigate the Venus flytrap’s signaling cascade involved in the prey capturing and digestion, we monitored the electrical activity of a prey-catching flytrap via surface electrode measurements,” the scientists said. “For these experiments we used crickets 6-12 mm in length, with an average weight of 23.8 mg.”
Once the traps close, “the still-moving victim continues to activate these mechanosensors, prolonging the electrical stimulation for many hours,” suggesting processes to breakdown prey continue for many hours after capture.
At closure, the plant releases a hormone called jasmonate which is an acid used by some plants for defense. Digestive enzymes are then released, as well as transporters to absorb nutrients. Glands on the inner surface of the trap also allows the plant to scale its production of costly ingredients to the size of the meal.
“The number of action potentials informs the plant about the size and nutrient content of the struggling prey. This allows the Venus flytrap to balance the cost and benefit of hunting,” Dr. Hedrich said.
The plants also show a marked increase in the ability to produce sodium during a capture. Scientists suggest that it may have something to do with how Venus flytraps maintain the right balance of water inside their cells.