Unsteady aerodynamic mechanisms underpinning animal flight have recently been intensively studied, but less well understood are those evolutionary pathways leading to the acquisition and subsequent elaboration of flapping flight. Recently discovered behaviors in Neotropical canopy ants demonstrate directed aerial descent in the complete absence of wings; controlled aerial behavior appears to have preceded the origin of wings in insects and other flying animals. Variation in atmospheric composition during the late Paleozoic may have influenced the initial evolution and subsequent diversification of insects, as well as the widespread phenomenon of arthropod gigantism, including but not limited to dragonflies with a 70 centimeter wingspan. For fully flighted forms, judicious use of helium to create physically variable gas mixtures permits decoupling of physiological from aerodynamic constraints on hovering performance. Such constraints are revealed in natural contexts through the study of hummingbird and bumblebee flight capacity across steep altitudinal transects.
Coffee and cookies before the presentation at 3:20 pm, and refreshments after the presentation will both be served in Room 128.