Meeting Abstract
The principles of aerodynamic lift generation imply that body weight support can be derived from any number of strategies depending on different combinations of species ecology, kinematics, and wing morphology. We show that across hummingbird species, scaling of lift generation is driven solely by hyperallometric growth of wing area, while tip velocity, air density, and lift coefficient are all size invariant. How this phenotype has arisen depends on whether it is an extension of phenotypes observed within species (i.e., developmental conservation), or is instead the result of selection. In contrast with the interspecific phenotype, but in accordance with the central role of wing velocity modulation observed in laboratory studies, hummingbirds exhibit intraspecific wing area hypoallometry and compensate with a strong dependence on wing velocity modulation. Hypoallometry of wing area within species likely minimizes muscle power requirements by reducing the wing moment of inertia, but potentially at the cost of reduced reserve burst power. Hyperallometric wing growth instead minimizes power requirements and maximizes reserve wing velocity, but at a large cost in torque. Though this evolutionary strategy has evidently been effective within the body size range of hummingbirds, the great muscle power requirements may have ultimately limited maximum hummingbird body mass.
