A Novel Interception Strategy in a Miniature Robber Fly with Extreme Visual Acuity

Trevor Wardill, Samuel Fabian, Ann Pettigrew, Doekele Stavenga, Karin Nordstrom, Paloma Gonzalez-Bellido

    Research output: Contribution to journalArticlepeer-review

    60 Citations (Scopus)


    Our visual system allows us to rapidly identify and intercept a moving object. When this object is far away, we base the trajectory on the target's location relative to an external frame of reference [1]. This process forms the basis for the constant bearing angle (CBA) model, a reactive strategy that ensures interception since the bearing angle, formed between the line joining pursuer and target (called the range vector) and an external reference line, is held constant [2–4]. The CBA model may be a fundamental and widespread strategy, as it is also known to explain the interception trajectories of bats and fish [5, 6]. Here, we show that the aerial attack of the tiny robber fly Holcocephala fusca is consistent with the CBA model. In addition, Holcocephala fusca displays a novel proactive strategy, termed “lock-on” phase, embedded with the later part of the flight. We found the object detection threshold for this species to be 0.13°, enabled by an extremely specialized, forward pointing fovea (∼5 ommatidia wide, interommatidial angle Δφ = 0.28°, photoreceptor acceptance angle Δρ = 0.27°). This study furthers our understanding of the accurate performance that a miniature brain can achieve in highly demanding sensorimotor tasks and suggests the presence of equivalent mechanisms for target interception across a wide range of taxa. Video Abstract

    Original languageEnglish
    Pages (from-to)854-859
    Number of pages6
    JournalCurrent Biology
    Issue number6
    Publication statusPublished - 20 Mar 2017


    • flight
    • interception strategy
    • invertebrate
    • moving target
    • predation
    • retina
    • spatial resolution
    • tracking
    • vision


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