Pollen counting made easy: mobile pollen counter provides real-time results in the field

Understanding the dynamics of pollen release is critical for studying plant reproductive strategies, particularly in systems where pollen is aerosolized, such as wind- and buzz-pollinated flowers. However, quantifying airborne pollen remains labor-intensive and reliant on laboratory-based techniques, limiting the scope of experimental and field-based research. Here, we demonstrate the use of a handheld air particle counter as a rapid, portable, and precise method for quantifying pollen release in real time across diverse pollination systems. Using controlled vibration experiments on buzz-pollinated Melastomataceae flowers we compare pollen counts from the air particle counter to those obtained from conventional liquid particle counters. The handheld counter consistently reported more reasonable and more consistent pollen counts across species, likely due to its ability to capture dispersed pollen clouds regardless of release direction. High-speed video footage confirmed that traditional methods can miss significant portions of pollen due to directional variability from stamens with complex morphologies. We further show that the handheld particle counter is applicable beyond buzz-pollination by using it to quantify pollen release in artificial wind-pollination experiments with Betula sp. Additionally, the device allows for fine-scale measurements of pollen size distributions and real-time pollen release rates. We further show that this method is robust to variations in pollen concentration and particle speed, and that it can detect exponential decrease in concentration of wind-dispersed pollen with distance. Beyond pollen, we discuss potential applications of this technique in quantifying airborne spores, seeds, and pathogens. Our results highlight the utility of handheld particle counters for experimental fieldwork and open new avenues for studying airborne particle dispersal and reproductive trait evolution in plants.