Buzz Pollination: Investigations of Pollen Expulsion using the Discrete Element Method

Abstract

Buzz pollination involves the release of pollen from, primarily, poricidal anthers through vibrations generated by certain bee species. Despite previous experimental and numerical studies, the intricacies of pollen dynamics within vibrating anthers remain elusive due to the challenges in observing these small-scale, opaque systems. This research employs the discrete element method (DEM) to simulate the pollen expulsion process in vibrating anthers. By exploring various frequencies and displacement amplitudes, a correlation between the maximum jerk of anther walls and the initial rate of pollen expulsion is observed under translating oscillations. This study highlights that while increased vibration intensity enhances pollen release, the rate of increase diminishes at higher intensities. Our findings also reveal the significant role of pollen-pollen interactions, which account for upwards of one-third of the total collisions. Comparisons between poricidal and pseudoporicidal anther geometries suggest that pore size and shape also influence expulsion rates. This research provides a foundation for more comprehensive models that can incorporate additional factors such as cohesion, adhesion, and Coulomb forces, paving the way for deeper insights into the mechanics of buzz pollination and its variability across different anther types and vibration parameters.