Flight performance in bats and its ecomorphological implications

Iriarte, Jose A.

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Year:: 2008
Contributor:: Iriarte, Jose A. (creator); Swartz, Sharon (director); Breuer, Kenneth (reader); Irschick, Duncan (reader); Roberts, Thomas (reader); Gatesy, Stephen (reader); Brown University. Division of Biology and Medicine. Ecological and Evolutionary Biology (sponsor)
Genre:: theses
Subject:: ecomorphology; wing morphology; cynopterus brachyotis; fruit bat; Bats; Flight; Performance; Aerodynamics; Locomotion
Extent:: xviii, 155 p.
DOI: https://doi.org/10.7301/Z04F1P64

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Abstract:: It is widely assumed that differences in wing morphology among bat species are reflected by interspecific differences in flight performance, and consequently, in the way different bat species exploit environmental resources. Surprisingly, the aerodynamic consequences of differences in wing morphology for bats are not known, because few studies have actually quantified flight performance in bats. Instead, predictions of bat flight performance from analysis of wing morphology have been inferred based on the well-understood aerodynamics of airplanes. However, the structural characteristics of bat wings, such as the presence of flexible bones supporting a highly anisotropic and compliant membrane suggest that analyses based on fixed, rigid wings may not permit us to fully understand the aerodynamics of bat wings. This, and the fact that performance can be behaviorally modulated, underscore the need of empirical determination of flight performance in bats. In this dissertation, I investigate the disconnect between what airplane-based models of bat flights would predict, and what bats actually do. The three-dimensional kinematic analysis of 90-degree turns in fruit bats (Cynopterus brachyotis) indicates that their turning mechanisms are more complex than the simple bank-turns of airplanes, with temporal separation of changes in body rotations and flight direction in bats that improve turning performance. The mechanism described differs from those observed in birds and insects and emphasizes the importance of the upstroke phase of the wingbeat cycle. Kinematic complexity is not restricted to turning maneuvers but is also present during straight, level flight. As expected, bats changed their wingbeat kinematics in response to changes in flight speed and to experimental increases in wing-loading. However, changes in kinematics were non-uniform among individuals, especially in response to loading. Results indicate that there are multiple mechanisms to modulate the generation aerodynamic force and that bats exhibit kinematic flexibility to maintain enough level of performance. The complexities observed in the kinematics during flight maneuvers and the substantial effect of individual differences in response to changes in speed and loading strongly emphasize the need for measuring performance to better understand the relationship between wing morphology and the ecology of bats.
Notes:: Thesis (Ph.D.) -- Brown University (2008)

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Rights: In Copyright
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Iriarte, Jose A., "Flight performance in bats and its ecomorphological implications" (2008). Biology and Medicine Theses and Dissertations, Ecological and Evolutionary Biology Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.7301/Z04F1P64

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