Meeting Abstract
S1-1.4 Friday, Jan. 4 Guidance laws underlying prey capture in the dragonfly LEONARDO, A; Janelia Farm / HHMI leonardoa@janelia.hhmi.org
Dragonflies are aerial predators that intercept small flying insects. Classic studies from Olberg, using single high speed camera recordings of dragonflies foraging outdoors, have suggested that the basic mechanism underlying these interception flights is the active stabilization of prey on the dragonfly eye. However, to date there are no in-flight measurements of 3D head position, nor are there any quantitative descriptions of how prey position is converted into wing steering signals. We have begun to study the dynamics of dragonfly prey capture using a custom built camera array that allows us to measure the three-dimensional position and rotational state (Euler angles) of the head and wings of the dragonfly at high temporal resolution, as well as the center-of-mass of the dragonfly and its prey. These data are collected in an indoor flight arena, where we can track interception flights over a large spatial volume in reproducible environmental conditions, allowing us to studying the dynamics of foraging flights with complex maneuvering. Many of characteristics of the prey capture flight, such as the interception angle and position of the prey, are based on a short timescale prediction of the prey’s flight statistics ~100ms before takeoff. Once the interception flight has begun, a simple closed-loop guidance law, in which lateral acceleration is proportional to the angular velocity of the target and the dragonfly’s speed, is used as an estimator of future target location. Preliminary head kinematics data show prey stabilization begins with a saccadic head movement immediately prior to takeoff, and this “foveation” of the prey is maintained actively during flight through continual head rotation. During flight, prey position varies 5-10x less in head-centered coordinates than body centered coordinates. I will discuss the dynamics of each of these components of the interception flight, and their relation to the underlying neural control system.
