Meeting Abstract
85.1 Monday, Jan. 6 10:15 To pursue, or not to pursue, that is the question: A neuroethological investigation of dragonfly predation decisions LIN, H*; MISCHIATI, M; SIWANOWICZ, I; LEONARDO, A; HHMI Janelia Farm linh10@janelia.hhmi.org
The dragonfly is an ancient aerial predator that specializes in capturing flying insects. Apart from their exceptional flying abilities, dragonfly predation success hinges on their target selection and pursuit decisions. With substantial metabolic investments at stake, these decisions are under high selective pressure. In this study, we focus on quantifying the rules underlying these takeoff and pursuit abortion decisions in the Common Whitetail (Libellula Lydia). We presented dragonflies with prey motion varying in speed profile and location using a custom robotic system. The dragonflies took off only after some prey, and some pursuits were aborted in mid-air. We captured the 3D kinematics of the dragonfly head and body, as well as the prey, using a customized motion capture system. These data allow us to reconstruct the exact time-varying projection of the prey in the dragonfly’s visual field from prey detection to capture. We found that perched dragonflies made a rapid head saccade to any moving target above their body, bringing the target to within ±10° azimuth and ±30° elevation from the center of the fovea. Following the saccade, smooth head tracking refined the alignment in both axes. In cases of pursuit, the foveation at takeoff was within 5° and was maintained throughout the flight. Pursuit abortion tended to occur when the target drift rate was high. Prompted by these behavioral data, we investigated the role of the target selective descending neurons (TSDNs) in these critical decisions. We recorded extracellularly from TSDNs in immobilized dragonflies and examined their responses to reconstructed visual experiences from real prey capture events. Then we attempted to elicit head saccades and pursuits while recording from TSDNs via a telemetry backpack.
