|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
How cockatiels (Nymphicus hollandicus) modulate pectoralis power output across flight speeds
1 Concord Field Station, Museum of Comparative Zoology, Harvard University,
Old Causeway Road, Bedford, MA 01730, USA
2 Department of Biology, University of Portland, 5000 N. Willamette
Boulevard, Portland, OR 97203, USA
* Author for correspondence (e-mail: thedrick{at}oeb.harvard.edu)
Accepted 29 January 2003
The avian pectoralis muscle must produce a varying mechanical power output to achieve flight across a range of speeds (1-13 m s-1). We used the natural variation in the power requirements with flight speed to investigate the mechanisms employed by cockatiels (Nymphicus hollandicus) to modulate muscle power output. We found that pectoralis contractile function in cockatiels was generally conserved across speed and over a wide range of aerodynamic power requirements. Despite the 2-fold range of variation in muscle power output, many aspects of muscle performance varied little: duration of muscle shortening was invariant, and overall wingbeat frequency and muscle strain varied to a lesser degree (1.2-fold and 1.4-fold, respectively) than muscle power or work. Power output was primarily modulated by muscle force (accounting for 65% of the variation) rather than by muscle strain, cycle frequency or changes in the timing of force production relative to muscle strain. Strain rate and electromyogram (EMG) results suggest that the additional force was provided via increasing pectoralis recruitment. Due to their effect on the transformation of muscle work into useful aerodynamic work, changes in wing position and orientation during the downstroke probably also affect the magnitude of muscle force developed for a given level of motor recruitment. Analysis of the variation in muscle force and airflow over the wing suggests that the coefficients of lift and drag of the wing vary 4-fold over the speed range examined in this study.
Key words: cockatiel, Nymphicus hollandicus, flight, muscle, power
This article has been cited by other articles:
|
|
 |
|
  T. J. Roberts and A. M. Gabaldon Interpreting muscle function from EMG: lessons learned from direct measurements of muscle force Integr. Comp. Biol., August 1, 2008; 48(2): 312 - 320. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. J. Parsons, T. Pfau, M. Ferrari, and A. M. Wilson High-speed gallop locomotion in the Thoroughbred racehorse. II. The effect of incline on centre of mass movement and mechanical energy fluctuation J. Exp. Biol., March 15, 2008; 211(6): 945 - 956. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. W. Tobalske and A. A. Biewener Contractile properties of the pigeon supracoracoideus during different modes of flight J. Exp. Biol., January 15, 2008; 211(2): 170 - 179. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Ellerby and G. N. Askew Modulation of flight muscle power output in budgerigars Melopsittacus undulatus and zebra finches Taeniopygia guttata: in vitro muscle performance J. Exp. Biol., November 1, 2007; 210(21): 3780 - 3788. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Ellerby and G. N. Askew Modulation of pectoralis muscle function in budgerigars Melopsitaccus undulatus and zebra finches Taeniopygia guttata in response to changing flight speed J. Exp. Biol., November 1, 2007; 210(21): 3789 - 3797. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. Jones, K. S. Lucey, and D. J. Ellerby Efficiency of labriform swimming in the bluegill sunfish (Lepomis macrochirus) J. Exp. Biol., October 1, 2007; 210(19): 3422 - 3429. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. W. Tobalske Biomechanics of bird flight J. Exp. Biol., September 15, 2007; 210(18): 3135 - 3146. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. T. Richards and A. A. Biewener Modulation of in vivo muscle power output during swimming in the African clawed frog (Xenopus laevis) J. Exp. Biol., September 15, 2007; 210(18): 3147 - 3159. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. L. Hedrick, J. R. Usherwood, and A. A. Biewener Low speed maneuvering flight of the rose-breasted cockatoo (Eolophus roseicapillus). II. Inertial and aerodynamic reorientation J. Exp. Biol., June 1, 2007; 210(11): 1912 - 1924. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. W. Tobalske and K. P. Dial Aerodynamics of wing-assisted incline running in birds J. Exp. Biol., May 15, 2007; 210(10): 1742 - 1751. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. W. Tobalske, L. A. Puccinelli, and D. C. Sheridan Contractile activity of the pectoralis in the zebra finch according to mode and velocity of flap-bounding flight J. Exp. Biol., August 1, 2005; 208(15): 2895 - 2901. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Soman, T. L. Hedrick, and A. A. Biewener Regional patterns of pectoralis fascicle strain in the pigeon Columba livia during level flight J. Exp. Biol., February 15, 2005; 208(4): 771 - 786. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. R. Usherwood, T. L. Hedrick, C. P. McGowan, and A. A. Biewener Dynamic pressure maps for wings and tails of pigeons in slow, flapping flight, and their energetic implications J. Exp. Biol., January 15, 2005; 208(2): 355 - 369. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Tu and T. L. Daniel Submaximal power output from the dorsolongitudinal flight muscles of the hawkmoth Manduca sexta J. Exp. Biol., December 15, 2004; 207(26): 4651 - 4662. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. L. Hedrick, J. R. Usherwood, and A. A. Biewener Wing inertia and whole-body acceleration: an analysis of instantaneous aerodynamic force production in cockatiels (Nymphicus hollandicus) flying across a range of speeds J. Exp. Biol., April 15, 2004; 207(10): 1689 - 1702. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. L. Marsh, D. J. Ellerby, J. A. Carr, H. T. Henry, and C. I. Buchanan Partitioning the Energetics of Walking and Running: Swinging the Limbs Is Expensive Science, January 2, 2004; 303(5654): 80 - 83. [Abstract] [Full Text] [PDF]
|
|
