Fast Reference-Locking in Hover Feeding Hawkmoths

Tracking and stabilization involves control around a fixed point. Depending on the method of control, this may or may not require memory in the form of a reference-point. While insects perform a wide range of memory-based behaviors, the fast formation and forgetting of reference points for control, has not been described before. We observed kinematics evidence for a short-term, remembered reference-point in hover-feeding behavior of hawkmoths. Using time-series analysis, we show that this behavior is mean-reverting, and the reference-point is forgotten and re-formed at the start of each feeding bout. While this indicates a neural substrate for short-term memory, the specific form of this memory depends on whether the behavior is driven by an integrator-with-reset (PI control on velocity), or by an explicit snapshot of spatial position (PD control on position). We are using robotic flowers and gaming monitors to distinguish between these possibilities.