Meeting Abstract

85.2  Monday, Jan. 6 10:30  Active head control and its role in steering during dragonfly interception flights MISCHIATI, M.*; LIN, H.; SIWANOWICZ, I.; LEONARDO, A.; HHMI Janelia Farm Research Campus mischiatim@janelia.hhmi.org

During high-speed interception flights, dragonflies make continuous head movements. These movements are hypothesized to hold prey foveated in a high acuity zone of the dorsal eye, and drift in foveation is thought to reflect unexpected prey movement and signal a need for steering (Olberg et al., 2007). However, drift in foveation is not merely a function of prey movement; instead, it also depends on the dragonfly’s own body and head rotation, and on the dragonfly’s movement relative to the prey. To investigate the effect of these factors on the quality of foveation, and the implications for steering control, we measured for the first time the full 3D head and body kinematics of the dragonfly Libellula Lydia, while it pursued actuated artificial prey. We found that prey were actively stabilized in the dorsal fovea by head rotations (RMS drift 5° in head coordinates, vs. 13° in body coordinates). Prey movement also drove changes in the dragonfly’s interception course, except during the initial post-takeoff maneuver that the dragonfly performed to gradually orient its bearing towards the prey. Surprisingly, the dominant disturbance to foveation came from the dragonfly’s own wing-stroke induced body oscillation. All self-induced drifts in foveation by rotation or translation of the dragonfly’s body were actively damped with counter-phased head rotations that had virtually zero delay to the disturbance itself, suggesting a predictive or proprioceptive driving mechanism. Active head control thus ensures that the visual system only experiences significant prey drift when large and unexpected prey steering occurs. This implies that visual feedback is integrated with other mechanisms that maintain the interception course when the prey is not maneuvering.