The Generation of Forces and Moments during Visual-Evoked Steering Maneuvers in Flying Drosophila
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.
© 2009 Sugiura et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received: January 12, 2009; Accepted: February 18, 2009; Published: March 20, 2009. We thank Michael B. Reiser, William B. Dickson and Andrew D. Straw for technical advice and assistance. We also thank Jasper C. Simon for weighing 96 fly stocks. Author Contributions: Conceived and designed the experiments: HS MD. Performed the experiments: HS. Analyzed the data: HS. Contributed reagents/materials/analysis tools: MD. Wrote the paper: HS MD. The authors have no support or funding to report. The authors have declared that no competing interests exist.
Published - journal.pone.0004883.PDF