Prof Thomas Daniel Chair and Joan and Richard Komen Professor Department of Biology University of Washington Box 35-1800, Seattle WA 98195-1800, USA [email protected] Thomas Daniel is the Chair and Joan and Richard Komen Professor of Biology at the University of Washington. He received his Bachelor’s and Master’s Degrees from the University of Wisconsin where he worked on drag reduction mechanisms in fish. He later received a Ph.D. from Duke University where his research focused on unsteady aspects of aquatic locomotion. He had postdoctoral training at the California Institute of Technology, where he studied unsteady flexing foil fluid dynamics. He was appointed to the faculty at the University of Washington in 1984 and currently is chair of Biology. He has received awards from the University for teaching, graduate mentorship and from MacArthur foundation. His current research focuses on the dynamics and control of flight in insects and on the molecular basis of force generation in muscle. Flight Dynamics in the Hawk Moth Manduca sexta Hawk moths fly under low light conditions, capable of hovering while feeding from moving flowers. They process both visual and mechano-sensory information to control a variety of actuators (wings and abdominal motions) that affect the flight path. This talk will review the diverse elements of flight control in the hawk moth, highlighting recent advances in our understanding of the aerodynamics of flight and its control. We focus on two themes: (1) sensory-motor integration of flight control which shows that abdominal motions are coupled to both visual and mechano-sensory input and (2) the emergent dynamics of highly compliant wings. In our analysis of the role of abdominal motions, we show that significant shifts in the center of gravity can lead to changes in the flight path. These shifts correlations are shown for freely flying individuals and those subjected to direct stimulation of the abdominal musculature. Moreover, both visual and mechano-sensory information drive abdominal motions in both the pitch and yaw planes, though with vastly different time constants (~80 ms delays for visual systems; ~10 ms delay for mechano-sensory systems). The ability to drive abdominal shifts via electrical stimulation allows us to test hypothesis about the role of the abdomen in flight control. While abdominal motions present an intriguing part of the flight control system, wings (particularly highly compliant ones) are clearly the most significant contributors to path control. While significant strides have been made in aerodynamic and kinematic studies of Dipteran (fly) wings, relatively less is known about wings that deform significantly during flight. As a second theme in this talk, we address the consequences of wing deformation to the flight control system. We show that hawk moth wings deform significantly during flight, manifest as large amplitude bending waves propagating chordwise along the wing. Moreover, using particle image velocimetry, we show that there are significant changes in the flux of momentum that are correlated with wing deformations.