Experiments in Fluids

, 46:873

Aerodynamic and functional consequences of wing compliance

Research Article


A growing body of evidence indicates that a majority of insects experience some degree of wing deformation during flight. With no musculature distal to the wing base, the instantaneous shape of an insect wing is dictated by the interaction of aerodynamic forces with the inertial and elastic forces that arise from periodic accelerations of the wing. Passive wing deformation is an unavoidable feature of flapping flight for many insects due to the inertial loads that accompany rapid stroke reversals—loads that well exceed the mean aerodynamic force. Although wing compliance has been implicated in a few lift-enhancing mechanisms (e.g., favorable camber), the direct aerodynamic consequences of wing deformation remain generally unresolved. In this paper, we present new experimental data on how wing compliance may affect the overall induced flow in the hawkmoth, Manduca sexta. Real moth wings were subjected to robotic actuation in their dominant plane of rotation at a natural wing beat frequency of 25 Hz. We used digital particle image velocimetry at exceptionally high temporal resolution (2,100 fps) to assess the influence of wing compliance on the mean advective flows, relying on a natural variation in wing stiffness to alter the amount of emergent deformation (freshly extracted wings are flexible and exhibit greater compliance than those that are desiccated). We find that flexible wings yield mean advective flows with substantially greater magnitudes and orientations more beneficial to lift than those of stiff wings. Our results confirm that wing compliance plays a critical role in the production of flight forces.

Supplementary material

348_2008_607_MOESM1_ESM.mov (269 kb)
Supplementary material 1 (MOV 269 kb)

Supplementary material 2 (MOV 245 kb)


  1. Bergou A, Xu S, Wang Z (2007) Passive wing pitch reversal in insect flight. J Fluid Mech 591:321–337MATHCrossRefGoogle Scholar
  2. Biewener A, Dial K (1995) In-vivo strain in the humerus of pigeons (Columba livia) during flight. J Morphol 225:61–75CrossRefGoogle Scholar
  3. Carruthers A, Thomas A, Taylor G (2007) Automatic aeroelastic devices in the wings of a steppe eagle Aquila nipalensis. J Exp Biol 210:4136–4149CrossRefGoogle Scholar
  4. Combes SA, Daniel TL (2001) Shape, flapping and flexion: wing and fin design for forward flight. J Exp Biol 204:2073–2085Google Scholar
  5. Combes S, Daniel T (2003a) Flexural stiffness in insect wings I. Scaling and the influence of wing venation. J Exp Biol 206:2979–2987CrossRefGoogle Scholar
  6. Combes S, Daniel T (2003b) Flexural stiffness in insect wings II. Spatial distribution and dynamic wing bending. J Exp Biol 206:2989–2997CrossRefGoogle Scholar
  7. Combes S, Daniel T (2003c) Into thin air: contributions of aerodynamic and inertial-elastic forces to wing bending in the hawkmoth Manduca sexta. J Exp Biol 206:2999–3006CrossRefGoogle Scholar
  8. Dickinson M, Gotz K (1996) The wake dynamics and flight forces of the fruit fly Drosophila melanogaster. J Exp Biol 199:2085–2104Google Scholar
  9. Ellington CP (1984) The aerodynamics of hovering insect flight. III. Kinematics. Philos T R Soc B 305:41–78CrossRefGoogle Scholar
  10. Ellington CP (1995) Unsteady aerodynamics of insect flight. In: Ellington CP, Pedley TJ (eds) Unsteady aerodynamics of insect flight. The Company of Biologists, Cambridge, pp 109–129Google Scholar
  11. Ennos AR (1988) The inertial cause of wing rotation in Diptera. J Exp Biol 140:161–169Google Scholar
  12. Ennos AR (1995) Mechanical-behavior in torsion of insect wings, blades of grass and other cambered structures. Proc Roy Soc Lond B Biol 259:15–18CrossRefGoogle Scholar
  13. Hedenstrom A, Johansson L, Wolf M, Von BR, Winter Y, Spedding G (2007) Bat flight generates complex aerodynamic tracks. Science 316:894–897CrossRefGoogle Scholar
  14. Hedrick TL (2008) Software techniques for two- and three-dimensional kinematic measurements of biological and biomimetic systems. Bioinspir Biomim 3:034001CrossRefGoogle Scholar
  15. Norberg R (1972) Evolution of flight in insects. Zoologica Scripta 1:247–250CrossRefGoogle Scholar
  16. Sane SP (2003) The aerodynamics of insect flight. J Exp Biol 206:4191–4208CrossRefGoogle Scholar
  17. Sane S, Dickinson M (2002) The aerodynamic effects of wing rotation and a revised quasi-steady model of flapping flight. J Exp Biol 205:1087–1096Google Scholar
  18. Sveen JK (2004) An introduction to MatPIV v. 1.6.1, Eprint No. 2, Department of Mathematics, University of Oslo. http://www.math.uio.no/~jks/matpiv
  19. Swartz S, Bennett M, Carrier D (1992) Wing bone stresses in free flying bats and the evolution of skeletal design for flight. Nature 359:726–729CrossRefGoogle Scholar
  20. Weis-Fogh T (1973) Quick estimates of flight fitness in hovering animals, including novel mechanisms for lift production. J Exp Biol 59:169–230Google Scholar
  21. Willmott A, Ellington C (1997) The mechanics of flight in the hawkmoth Manduca sexta.1. Kinematics of hovering and forward flight. J Exp Biol 200:2705–2722Google Scholar
  22. Wootton RJ (1981) Support and deformability in insect wings. J Zool 193:447–468CrossRefGoogle Scholar
  23. Wootton RJ (1992) Functional morphology of insect wings. Annu Rev Entomol 37:113–140CrossRefGoogle Scholar
  24. Wootton RJ (1993) Leading-edge section and asymmetric twisting in the wings of flying butterflies (Insecta, Papilionoidea). J Exp Biol 180:105–117Google Scholar
  25. Wootton RJ, Herbert RC, Young PG, Evans KE (2003) Approaches to the structural modelling of insect wings. Philos T R Soc B 358:1577–1587CrossRefGoogle Scholar
  26. Wu TY (1971) Hydrodynamics of swimming propulsion. Part 1. Swimming of a two-dimensional flexible plate at variable forward speeds in an inviscid fluid. Part 2. Some optimum shape problems. Part 3. Swimming and optimum motions of slender fish with side fins. J Fluid Mech 46:337–355CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of BiologyUniversity of WashingtonSeattleUSA

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