Meeting Abstract

54.2  Sunday, Jan. 5 13:45  Kinematics and aerodynamics of escape responses to looming stimuli in freely flying fruit flies MUIJRES, FT*; MELIS, J; ELZINGA, MJ; DICKINSON, MH; University of Washington, Seattle; Delft University of Technology, the Netherlands; University of Washington, Seattle; University of Washington, Seattle fmuijres@uw.edu

Flying insects possess a range of stereotypic flight responses that are triggered by particular sensory stimuli. Arguably, one of the most extreme flight responses is the evasive maneuver in response to looming stimuli, which enables an animal to avoid collisions and escape from approaching predators. Here, we study the aerodynamics and body and wing kinematics of visually-elicited evasive maneuvers in freely flying fruit flies. Using an array of high-speed cameras (7,500 frames per second), we tracked body and wing kinematics throughout the behavioral response. The maneuvers were triggered using a circular looming stimulus displayed on the arena walls, which consisted of a cylindrical array of LEDs. The wing kinematics were extracted using an automated tracking routine and were replayed using a dynamically-scaled mechanical model of a fruit fly to study the aerodynamic forces and moments that govern the maneuver. The free-flight experiments show that rapid evasive maneuvers in fruit flies consist of four overlapping components: 1) a fast body roll, followed by 2) a counter-roll, 3) a pitch-up body rotation, and 4) an increase in total force production. As a result, the wing stroke plane, and as a consequence, the average flight force vector are directed away from the looming threat. Our results show that the fly controls roll, pitch, and flight force independently, by varying distinct kinematic features of its wing motion on a wingbeat-to-wingbeat basis.