Flying spiders: Effects of the spider mass and the dragline length in spider landing

Many spiders use aerial dispersal "ballooning" to move from one location to another. By ballooning, spiders can reach distances as far as 3200 km and heights up to 5 km. Although this process is exhibited regularly in nature, little is known about the dynamics at play. What dominates the three stages of spider takeoff, flight, and settling? Understanding the roles of multiple parameters, including a spider's mass, morphology, posture, dragline properties, and local meteorological conditions (turbulent level and thermal stability, is not only of ecological significance but critical to improving advanced technologies for bio-inspired innovations of airborne robotic devices. Here we pose a controlled lab experiment to test for the characteristics of free fall landing. We seek to determine how the dragline length and spider mass affect the dynamics of freefall at Reynolds numbers of several thousand using high-speed recordings. Such results are expected to shed light on the intriguing flow physics of spider ballooning and validate new models.