Venus flytraps count the number of touches from trapped insect prey before producing digestive juices.

Credit: 237/Adam Gault/Ocean/Corbis

Erwin Neher at the Max Planck Institute for Biophysical Chemistry in Göttingen and Rainer Hedrich of the University of Würzburg, both in Germany, and their colleagues touched the leaves of Venus flytraps (Dionaea muscipula; pictured) to mimic captured, moving prey. They recorded the plant's electrical impulses in response to 1–60 touches, and found that two impulses triggered the trap to close. But only after the fifth impulse did plants begin to synthesize the digestive enzyme hydrolase and increase their production of a sodium transporter, which is used to absorb nutrients.

Venus flytraps may record the touches of potential prey to identify insects that are worth digesting, the authors say.

Curr. Biol. (2016)