According to a study by German scientists, Venus flytraps can “count” the number of times a struggling insect touches their trigger hairs and use this information to ramp up their digestion.
For the study, published in the journal Current Biology, the team used a machine to simulate an insect touching a Venus flytrap. They found that each numbered pulse/touch was associated with an individual response. For example, two touches trigger a hormone increase; five bring on the production of digestive enzymes.
“The number of action potentials informs [the plant] about the size and nutrient content of the struggling prey,” project leader, Rainer Hedrich explained. “This allows the Venus flytrap to balance the cost and benefit of hunting.”
Digestion generally takes between five to twelve days, depending on the size of the meal. During that time, the plants absorb carbon, nitrogen, phosphate and sulfur from their prey, but one observation the team made from the study was that the plants also show a marked increase in production of a transporter that allows them to take up sodium. They aren’t yet sure on the reasoning behind this, but it may be related to how carnivorous plants maintain the balance of water inside their cellular walls.
The researchers are now sequencing the Venus flytrap genome to attempt to reveal more on how the plants evolved to support their meat-loving ways.