A single touch can provide sufficient mechanical stimulation to trigger Venus flytrap closure.

Hans J. Herrmann,Falk K. Wittel,Hannes Vogler,Ueli Grossniklaus,Ingo Burgert,Jan T. Burri,Bradley J. Nelson,Eashan Saikia,Markus Rüggeberg,Nino F. Läubli

doi:10.1371/journal.pbio.3000740

Hans J. Herrmann, Falk K. Wittel + Show 8 more

Open Access

https://doi.org/10.1371/journal.pbio.3000740

Copy DOI

Abstract

The carnivorous Venus flytrap catches prey by an ingenious snapping mechanism. Based on work over nearly 200 years, it has become generally accepted that two touches of the trap's sensory hairs within 30 s, each one generating an action potential, are required to trigger closure of the trap. We developed an electromechanical model, which, however, suggests that under certain circumstances one touch is sufficient to generate two action potentials. Using a force-sensing microrobotic system, we precisely quantified the sensory-hair deflection parameters necessary to trigger trap closure and correlated them with the elicited action potentials in vivo. Our results confirm the model's predictions, suggesting that the Venus flytrap may be adapted to a wider range of prey movements than previously assumed.

Highlights

The hunting mechanism of the carnivorous Venus flytrap (Dionaea muscipula), according to Darwin “the most wonderful plant in the world” [1], has attracted the interest of many scientists, starting with the observations made by Edwards and Nutall, who described the excitability of the sensory hairs but still thought that the capture of insects was accidental [2,3]
Reasoning that hair deflection induced by spiders, ants, and flies—i.e., the “classical” prey of D. muscipula [21]—would be rather quick, we operated the microrobotic system at full speed to simulate these stimuli, resulting in high initial angular velocities ranging from 10 to 20 rad s−1
This is in the same range as Scherzer and colleagues found for moving ants, which deflect the sensory hair with an angular velocity of 0.25–7.8 rad s−1 [20] but much slower than the leg movements of houseflies [22]

Summary

Introduction

The hunting mechanism of the carnivorous Venus flytrap (Dionaea muscipula), according to Darwin “the most wonderful plant in the world” [1], has attracted the interest of many scientists, starting with the observations made by Edwards and Nutall, who described the excitability of the sensory hairs but still thought that the capture of insects was accidental [2,3]. In the 1830s, Curtis realized that the traps were devoted to catching animal prey [4]. The individual phases—from trap triggering to reopening after successful digestion —have been investigated from different angles (reviewed in [5]).

Methods

Results

Conclusion