Meeting Abstract
Aerial locomotion has evolved repeatedly and has allowed organisms to occupy habitats and exploit resources that would otherwise be unavailable. Controlled aerial behavior has evolved frequently in arboreal taxa via the mechanism of directed aerial descent, likely because all such organisms frequently experience falls. Many of these organisms lack dedicated airfoils yet exhibit considerable control over their velocity and trajectory while airborne. The flat-tailed house gecko (Hemidactylus platyurus) has been observed falling with limbs outstretched, and has shown to engage in aerial control through use of their tails to influence pitch, roll, and yaw. However, any active role of their limbs has not yet been documented. During free fall, these geckos perform reciprocating limb motions whereby the forelimbs synchronously move cranioventrally and caudodorsally. This study characterized the kinematics of such limb motions and their effects on aerial performance. We simulated directed aerial descent in six falling H. platyurus individuals through use of a vertically oriented wind tunnel, filmed ten aerial trials for each individual at 400 frames per second, and selected the five exemplary trials for analysis. We used MATLAB software to digitize and reconstruct the lizards’ movements in three dimensions, as well as to estimate their velocities by using the first derivative of a quintic spline smoothing algorithm. Initial data suggest a strong correlation between forelimb motions and translational body velocity, suggesting a selective advantage to incipient limb flapping in aerial squamates.
