Meeting Abstract
Suction feeding is the most common feeding mode in large aquatic organisms. Previous studies on fish showed that suction feeding requires considerable power, leading fish to recruit axial muscles or use elastic energy storage. Having no muscles, carnivorous plants use elastic energy storage to power fast motion. Here, we focus on two bladderwort species, Utricularia gibba and Utricularia australis, which catch zooplankton prey in millimeter-sized suction traps. Bladderworts are among the smallest and fastest suction feeders, with trap gapes of around 0.2 mm (median diameter at the mouth) and times-to-peak-flow of less than 1 millisecond. In this study we quantify the flow in front of the traps, using particle image velocimetry, to estimate the power generated during capture events. We found that suction events generate flow speeds at half gape from the vestibule that range from 0.13 to 0.37 m/s with median speeds around 0.15 m/s for U. gibba and 0.25 m/s for U. australis. These flow speeds are two orders of magnitude higher than those observed in larval fish with comparable gape diameters. We also observed that the time to peak flow speed is one to two orders of magnitude lower in bladderworts than in comparable larval fish. This combination of higher peak flow speeds and higher accelerations leads to considerably higher power estimates than those obtained for fish. Animals can reach similar powers using elastic mechanisms, yet we do not know which constraints prevent larval fish from reaching similar suction performances as bladderwort traps.
