P3.142 Friday, Jan. 6 Sideslipping Maneuvers in Free-Flying Hawkmoths GREETER, Jeremy SM*; HEDRICK, Tyson L; University of North Carolina at Chapel Hill email@example.com
Pilots envy the ability of some flying insects to dart in any direction with seeming ease. Recent research revealed some of the biological and mechanical rules that govern these maneuvers in insects both large and small. These studies include investigations of yaw rotations in Drosophila and hawkmoths (Dickinson et al., doi:10.1126/science.284.5422.1954, Hedrick et al., doi:10.1126/science.1168431), and the pitch stability of hovering insects (Sun & Wang, doi:10.1242/jeb.00457). Many birds, bats, and insects can also produce lateral or sideslip maneuvers, which we investigate here in the hawkmoth Manduca sexta. To elicit lateral movements, we oscillated a low-intensity light source above moths in a dark flight chamber, rather than training moths to follow flowers as in earlier experiments. This eliminated the unknown effects of an unfurled proboscis on flight mechanics and prevented it from mechanically coupling the moth to the moving target. We used high-speed infrared videography and 3D reconstruction to measure angular and translational kinematics of the moths and their wings in flight. We observed that hawkmoths use roll to create accelerations in the lateral plane during sideslip direction reversals. These roll-based sideslips differ from sideslips reported in D. melanogaster (Ristroph et al., doi:10.1242/jeb.025502), which initiate lateral accelerations by changing the relative timing of flips in the long-axis wing rotation angles of their left and right wings. Preliminary findings suggest hawkmoths initiate the roll maneuver that creates their lateral acceleration via stroke amplitude asymmetry. A potential reason for this diversity of sideslip maneuvers is the higher Reynolds number of hawkmoth flight and the shift towards downstroke-dominated force production in these larger fliers.