The Generation of Forces and Moments during Visual-Evoked Steering Maneuvers in Flying Drosophila

Hiroki Sugiura,Michael H Dickinson

doi:10.1371/journal.pone.0004883

Abstract

Sideslip force, longitudinal force, rolling moment, and pitching moment generated by tethered fruit flies, Drosophila melanogaster, were measured during optomotor reactions within an electronic flight simulator. Forces and torques were acquired by optically measuring the angular deflections of the beam to which the flies were tethered using a laser and a photodiode. Our results indicate that fruit flies actively generate both sideslip and roll in response to a lateral focus of expansion (FOE). The polarity of this behavior was such that the animal's aerodynamic response would carry it away from the expanding pattern, suggesting that it constitutes an avoidance reflex or centering response. Sideslip forces and rolling moments were sinusoidal functions of FOE position, whereas longitudinal force was proportional to the absolute value of the sine of FOE position. Pitching moments remained nearly constant irrespective of stimulus position or strength, with a direction indicating a tonic nose-down pitch under tethered conditions. These experiments expand our understanding of the degrees of freedom that a fruit fly can actually control in flight.

Highlights

Flying insects display stability, maneuverability, and robustness that are rarely matched by either fixed- or rotary-wing aircraft
Studies of blow flies suggest that the control of forces and moments are tightly coupled through the influence that individual steering muscles have on wing kinematics [19]
Each light-emitting diodes (LEDs) subtended approximately 3.75u. For these experiments we created translational patterns consisting of square wave gratings that moved in opposite directions on two sides of the arena creating a focus of expansion (FOE) and a focus of contraction (FOC) spaced 180u apart (Fig. 1D)

Summary

Introduction

Maneuverability, and robustness that are rarely matched by either fixed- or rotary-wing aircraft. Such performance has prompted interest in insect flight, both as a model system for sensory motor integration [1,2] and as a means of inspiration for developing new control algorithms for technological devices [3,4,5,6]. A fly might accomplish a simple avoidance reaction through a change in yaw, roll, sideslip, or a combined change in multiple forces and moments. Our approach here is to directly measure the forces and torques generated by tethered fruit flies in response to translational patterns of optic flow and to correlate them with observed changes in wing kinematics. The results indicate that the fruit flies are capable of generating sideslip and that visuallyelicited turning responses involve a coordinated change in both forces and moments

Methods

Results

Conclusion