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

Trevor J. Wardill, Samuel T. Fabian, Ann C. Pettigrew, Doekele G. Stavenga, Karin Nordstroem, Paloma T. Gonzalez-Bellido

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    64 Citations (Scopus)
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    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 (similar to 5 ommatidia wide, interommatidial angle Delta phi = 0.28 degrees, photoreceptor acceptance angle Delta rho = 0.27 degrees). 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.

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


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