Meeting Abstract
Bladderworts, aquatic carnivorous plants, use specialized traps (with a mouth opening of about 0.2mm in diameter) to complete their feeding strike in less than a millisecond after the prey triggers it. Suction feeding is well understood in animals with sizes greater than 1 centimeter and the little we know about small suction feeders from larval fish suggests that small suction feeders are not effective. Yet bladderworts have strong suction performances despite having the same mouth size as that of fish larvae. Previous studies of bladderwort suction feeding have focused on the trap door mechanics rather than the mechanics of fluid flow. As bladderwort suction flows are difficult to study due to the traps’ small size and fast prey capture feeding strike, we use a dynamically scaled mechanical model of the bladderwort trap. This model allows us to study hydrodynamic performance in greater detail by generating suction flows with a higher temporal and spatial resolution. The mechanical model comprises a constant-diameter cylinder and piston, actuated by a linear motor, submerged in mineral oil. The set-up is optimized for particle image velocimetry (PIV) to quantify flow and pressure fields by filming the flows with high-speed cameras. We simulate strike kinematics of actual traps as well as counterfactual scenarios of traps that are smaller and slower than real traps to explore how peak pressure and time to peak pressure affect suction performance. Our findings largely agree with theoretical models of suction flows, which show that pressure has a strong effect on flow speed. This dynamically scaled mechanical model is a valuable tool to address bio fluid-dynamic questions as it allows us to tease apart the role of pressure and time to peak pressure in generating fast, high pressure-gradient flows.
