Electrical impulses aren’t exclusive to animals. Plants such as the Venus Flytrap also use electricity to sense and react to the world. In this experiment, you’ll record action potentials from a Venus Flytrap and discover how a plant knows it’s an insect moving inside the trap.
The Venus Flytrap is a carnivorous plant that supplements its diet by trapping and digesting insects—an ingenious solution to the nutrient-poor, boggy soils of the Carolinas. Instead of growing deep roots to find scarce minerals, the Flytrap hacked nature by extracting nutrients from animals.
How can a plant sense a fly and capture it? That sounds like something an animal would do. Do plants have brains? What even counts as a brain? In this experiment, you’ll tackle these questions and uncover the physiology behind the Flytrap’s lightning-fast snap.
Materials:
Insert the black ground pin into the pot’s soil so the Plant SpikerBox has a stable reference.
The recording electrode goes on the trap (the leaf), while the ground stays in the soil. Press the orange stake electrode into the soil next to the trap you want to record from, so its silver wire rests against the outside of the trap. Put a dab of electrode gel where the wire touches the trap.
Connect the yellow lead to the Plant SpikerBox, red clip to the stake wire, and black clip to the ground wire. Power on the SpikerBox and launch SpikeRecorder.
Begin recording. Gently touch one of the trigger hairs inside the trap (there are three on each side, about six in total). Wait about 60 seconds between touches. The trap only snaps shut when two touches come within about 20 seconds of each other—that’s how it tells a moving insect from a raindrop—and closing a trap over and over can kill it.
Examine your recordings. Do you see spikes that resemble action potentials? How do their shapes and timing compare with those recorded from animals such as the cockroach leg? Observe the Flytrap’s behavior when you touch a trigger hair. Does it always respond? What patterns can you spot in the electrical signals and the trap’s movement?
Draw the trap as a system: what senses the insect (the trigger hairs), what carries the message (the electrical signal you recorded), and what moves (the two lobes of the trap). Mark where your recording electrode sat.
HS-LS1-2 Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.
Draw the trap as a system: trigger hairs that sense, an electrical signal that carries the message, lobes that close.
2 Developing and Using Models
Draw the trap as a system (what senses, what signals, what moves) and mark where you recorded.
3 Planning and Carrying Out Investigations
Record the trap while touching one trigger hair, a minute between touches.
4 Analyzing and Interpreting Data
Compare the plant's spikes with an animal action potential; look for patterns between signal and movement.
Cause and Effect
Touching a trigger hair sets off an electrical signal and the snap.
Structure and Function
Trigger hairs inside the trap (three on each side, about six in total) sense an insect.
Patterns
Look for patterns in the signals and the trap's movement.
LS1.A Structure and Function
Specialized structures — trigger hairs and the trap — sense and capture prey.
Backyard Brains mapping using the book's method. Not in the book. Performance expectation as the Backyard Brains Plant SpikerBox curriculum plan (2026) aligns this lesson; practices, crosscutting concepts and core ideas by the book's method.
