TrackFly: VR for free-flying fruit flies

A fruit fly flies upwind in a Virtual Reality (VR) controlled wind tunnel. Its 3D position is measured in real time using Trackit 3D and used to control optic flow projected on the side walls. By providing a sinusoidally modulated slip speed, the fly accelerates accordingly, causing it to ‘dance’ up wind.  

TrackFly is a “virtual reality” wind tunnel that allows behavioral responses of free-flying fruit flies to be tested in presence of a simulated visual environment. Immersing the fly in a semi-realistic, reactive visual environment allows a huge variety of behavioral experiments to be designed and flight responses to be measured in an automated fashion. The setup is currently used to uncover flight control principles in the fruit fly Drosophila.

The system consists of a standard flow-through wind tunnel equipped with Trackit 3D and and a custom-developed imaging system. The 3D position of one fly at a time is measured with a sampling rate of 50Hz and a latency of approximately 20ms. The 3D position is transferred via a network interface to the imaging system, whose custom programmed software calculates the desired image depending on the fly’s measured behavior. Finally, the image is projected onto two 1m wide, 0.3m high screens mounted on each side of the wind tunnel (total system latency ~40ms).