High-precision insect wing and body kinematics acquisition using a new and flexible free-flight arena

Abstract

During flight, insects can make subtle changes to their wing kinematics that in turn have large effects on their aerodynamic forces. To understand and model the above, therefore requires measurements of natural flight with appropriate spatiotemporal resolution and duration. These factors are determined by wingbeat frequency, size, and behaviour, which are limited by trade-offs within the operating equipment. Here, we describe a new and flexible arena setup that uses ten high-speed cameras to record insects flying freely in an optically clear chamber that can scale from the smallest to some of the largest insects. Pulsed far-red LEDs are focused and aligned with the high-speed cameras to provide bright, uniform backgrounds that eliminate motion blur and are beyond the insects’ visible spectrum. Separate, stereo cameras function as triggers, using real-time image analysis when subjects enter the recording volume. These triggers can control additional stimuli, such as a white light, to induce flight manoeuvres at specific times. The resultant footage is coupled with a comprehensive voxel-carving software package to automatically calculate wing and body kinematics. This includes wing deformations in the form of wing torsion, which is important for accurate aerodynamic modelling. To date, we have documented free-flight in several species, including Calliphora vicina and Drosophila melanogaster at 6,400 fps, and Anopheles gambiae at 12,000 fps. This setup will generate a large database of high-precision insect free-flight kinematics to better our understanding of this diverse class and be used to feed into studies of insect flight control and aerodynamics.