Predictive saccades and decision making in the beetle-predating saffron robber fly

Internal predictions about the sensory consequences of self-motion, encoded by corollary discharge, are ubiquitous in the animal kingdom, including for fruit flies, dragonflies, and humans. In contrast, predicting the future location of an independently moving external target requires an internal model. With the use of internal models for predictive gaze control, vertebrate predatory species compensate for their sluggish visual systems and long sensorimotor latencies. This ability is crucial for the timely and accurate decisions that underpin a successful attack. Here, we directly demonstrate that the robber fly Laphria saffrana, a specialized beetle predator, also uses predictive gaze control when head tracking potential prey. Laphria uses this predictive ability to perform the difficult categorization and perceptual decision task of differentiating a beetle from other flying insects with a low spatial resolution retina. Specifically, we show that (1) this predictive behavior is part of a saccade-and-fixate strategy, (2) the relative target angular position and velocity, acquired during fixation, inform the subsequent predictive saccade, and (3) the predictive saccade provides Laphria with additional fixation time to sample the frequency of the prey’s specular wing reflections. We also demonstrate that Laphria uses such wing reflections as a proxy for the wingbeat frequency of the potential prey and that consecutively flashing LEDs to produce apparent motion elicits attacks when the LED flicker frequency matches that of the beetle’s wingbeat cycle. [Display omitted] •Laphria robber flies categorize prey by cuing on to their wingbeat reflections•Before the attack, Laphria track prey with a predictive saccade-and-fixate strategy•The prey’s angular position and velocity informs Laphria’s predictive saccades•During fixations, Laphria extends prey sampling time with closed loop head tracking Prey capture requires timely and accurate decisions. Talley et al. show that the robber fly Laphria saffrana, a specialized beetle predator, cues onto the wing beat frequency of potential prey and tracks it with predictive saccade-and-fixate head movements. This strategy supports robust target categorization and fast perceptual decision making.