LeRoy Apker Award Talk: The Aerodynamics of Ballistic Seed Dispersal in the Plant Family Acanthaceae

Plants in the Acanthaceae family ballistically launch seeds that rotate at up to 1660 Hz – one of the fastest rotation rates in the natural world. In numerous species, this high rate of backspin stabilizes seeds in a streamlined orientation, which we have analytically determined is a property of all ballistic spinning discs. Using high-speed video, we quantify the effect that this stability has on aerodynamic drag and dispersal range. Study of several species within the Ruellia genus shows plants reach the largest seed dispersal ranges (up to 10 m) when utilizing the aerodynamic benefits of stable backspin. This research opens the door to further comparative study across the 4000+ species of the Acanthaceae family. Combining systematic measurements of seed dispersal aerodynamics with existing phylogenetic data promises to shed light on open biological questions about the adaptive significance of seed dispersal.