gwyneth card
Research:
The fruit fly, Drosophila melanogaster,
performs at least two distinct types of flight initiation. One kind is
a stereotyped escape response to a visual stimulus that is mediated by
the hard-wired giant fiber neural pathway, and the other is a more
variable ‘voluntary’ response that can be performed without giant fiber
activation. Because the simpler escape take-offs are apparently
successful, it is unclear why the fly has multiple pathways to
coordinate flight initiation. We use high-speed videography to observe
flight initiation in unrestrained wild-type flies and assess the flight
performance of each of the two types of take-off. Three-dimensional
kinematic analysis of take-off sequences indicates that wing use during
the jumping phase of flight initiation is essential for stabilizing
flight. During voluntary take-offs, early wing elevation leads to a
slower and more stable take-off. In contrast, during visually-elicited
escapes, the wings are pulled down close to the body during take-off,
resulting in tumbling flights in which the fly translates faster but
also rotates rapidly about all three of its body axes. Additionally, we
find evidence that the power delivered by the legs is substantially
greater during visually-elicited escapes than during voluntary
take-offs. We find that the two types of Drosophila flight initiation
result in different flight performances once the fly is airborne, and
that these performances are distinguished by a trade-off between speed
and stability.
Current Position:
Bioengineering Graduate Student, Dickinson Lab
California Institute of Technology, Pasadena, CA
Publications:
Card, G. & Dickinson, M. (2008). Visually-mediated motor planning in the escape response of Drosophila. Cur Biol 18:1300-07. abstract
Card, G. & Dickinson, M. (2008). Performance trade-offs in the flight initiation of Drosophila. J Exp Biol 211(Pt 3): 341-53 abstract
Taylor, P. E., Card, G., House, J., Dickinson, M. H., & Flagan, R. C. (2006). High-speed pollen release in the white mulberry tree, Morus alba L. Sexual Plant Reproduction 19 (1): 19-24 pdf file
Biewener, A. A., McGowan, C., Card, G. M., & Baudinette, R. V. (2004). Dynamics of leg muscle function in tammar wallabies (M. eugenii) during level versus incline hopping. J Exp Biol 207: 211-223 pdf file
Videos:
Lab webpage:
http://www.dickinson.caltech.edu/People/Gwyneth_Card