Phase-Dependent Visual Control of the Zigzag Paths of Navigating Wood Ants

Abstract

Animals sometimes take sinuous paths to a goal. Insects, tracking an odor trail on the ground [1-3] or moving up an odor plume in the air [4, 5], generally follow zigzag paths. Some insects [6-8] take a zigzag approach to visual targets, perhaps to obtain parallax information. How does an animal keep its overall path in the direction of the goal without disrupting a zigzag pattern? We describe here the wood ant's strategy when guided by a familiar visual scene. If their travel direction is correct, ants face the goal briefly after each turning point along their zigzag path. If the direction is wrong, they turn rapidly at this point to place the scene correctly on their retina. Such saccade-like turns are rare elsewhere in the zigzag. Similarly, when the scene is made to jump to a new position on their retina, ants wait until an expected goal-facing phase of the zigzag before turning to correct the imposed error. Correctly timed, intermittent control allows an animal to adjust its path without compromising additional roles for the zigzag pattern in gathering visual information or in using odor cues for guidance.

Route Following Without Scanning

“…The klinokinesis algorithm produced similar error scores as the visual compass methodology but used only 8% of the total number of image comparisons resulting in a marked improvement in speed in both robot and simulation trials. Further, the paths produced by the algorithm show a natural zig-zag pattern, which closely matches the fine-scale movement patterns reported in homing ants which are sinusoidal rather than straight [13][14][15].…”

Robust and Rapid Air-Borne Odor Tracking without Casting

“…A similar zigzag strategy is also observed in insects (Vickers, 2000; Willis and Avondet, 2005; Lent et al, 2013), fish (Montgomery et al, 1999; DeBose and Nevitt, 2008), and crustaceans (Weissburg and Zimmer-Faust, 1994; Basil et al, 2000; Vickers, 2000) that have to use odor information dispersed intermittently in fluid media. Apart from such zigzag tracking, animals may also switch between different strategies to compensate for stimulus perturbations, such as different odor gradients (Catania, 2006, 2013; Cardé and Willis, 2008; Reynolds et al, 2009; Gomez-Marin et al, 2010, 2011).…”

Scene perception and the visual control of travel direction in navigating wood ants

“…SLTs are preceded by a segment of a zig or zag in which goal angles (figure 3d bottom) are larger than they are in the corresponding segments of zigs and zags without SLTs (figure 3d top). In segments of the zig or zag immediately after an SLT, the goal angles do not differ from those of zigs or zags without SLTs [33]. SLTs, thus, occur at particular phases, when goal angles are typically small.…”