3-D Analysis of the Flight Trajectories of Flies

Drosoplriln, Tracking, Computer Reconstruction, Saccades, Free Flight We have developed a computer system for reconstructing and analyzing three dimensional flight trajectories of flies. Its application to the study of the free flight behaviour of the fruitfly Drosophiln rnelnnogaster is described. The main results are: a) Drosophila males only occasionally track other flies; b) in such cases the fly's angular velocity is a function of the error angle under which the leading fly is seen; c) body saccades can be demonstrated during cruising flights: d) high angular velocities are strongly correlated with low fonvard velocities, probably reflecting an aerodynamic constraint of flight. The 3-D technique described may provide an adequate tool for studying the organization of the systems present in flies and For relating the free flight behaviour to previous analyses of tethered flies.