Quantifying Prey-Induced Motion in Drosera capensis

Drosera capensis, a well-known carnivorous plant, traps prey using a wide range of folding dynamics and motions that are still poorly characterized. Here, we study the underlying physical rules and mechanisms that confer this wide breadth of behaviors. We use time-lapse photography to capture dynamics and final forms of our leaves and vary the placement, concentration, and distribution of food along the leaf. Using our own custom-written particle tracking code, we analyze the dynamics of this movement and how the various parameters influence motion. We find that both the capture dynamics and the final form conformations are influenced by the location, size, and distribution of the prey along the leaf, as well as the environmental humidity. Our particle tracking code revealed that leaf motion proceeds through distinct acceleration and relaxation phases, with characteristic timescales that vary systematically with prey mass and position. The total displacement and curvature rate increased nonlinearly with stimulus strength, suggesting a threshold-driven mechanical response. Our findings provide the first physical framework for the prey-trapping behavior of Drosera capensis leaves offering new insights into their non-muscular and energy-efficient motion.