Clement Leo, Schwarz Sebastian, Mahot-Castaing Blandine, Wystrach Antoine
Centre de Recherches sur la Cognition Animale, CNRS, Université Paul Sabatier, Toulouse 31062 cedex 09, France.
Department of Biology, University of Graz, 8010 Graz, Austria.
J Exp Biol. 2025 Mar 1;228(5). doi: 10.1242/jeb.249935. Epub 2025 Mar 7.
Solitary foraging insects such as desert ants rely heavily on vision for navigation. Although ants can learn visual scenes, it is unclear what cues they use to decide whether a scene is worth exploring at the first place. To investigate this, we recorded the motor behaviour of Cataglyphis velox ants navigating in a virtual reality setup and measured their lateral oscillations in response to various unfamiliar visual scenes under both closed-loop and open-loop conditions. In naturalistic-looking panorama, ants display regular oscillations as observed outdoors, allowing them to efficiently scan the scenery. Manipulations of the virtual environment revealed distinct functions served by dynamic and static cues. Dynamic cues, mainly rotational optic flow, regulated the amplitude of oscillations but not their regularity. Conversely, static cues had little impact on the amplitude but were essential for producing regular oscillations. Regularity of oscillations decreased in scenes with only horizontal, only vertical or no edges, but was restored in scenes with both edge types together. The actual number of edges, the visual pattern heterogeneity across azimuths, the light intensity or the relative elevation of brighter regions did not affect oscillations. We conclude that ants use a simple but functional heuristic to determine whether the visual world is worth exploring, relying on the presence of at least two different edge orientations in the scene.
独居觅食的昆虫，如沙漠蚂蚁，在导航时严重依赖视觉。尽管蚂蚁能够学习视觉场景，但尚不清楚它们最初是依据哪些线索来判断某个场景是否值得探索。为了研究这一问题，我们记录了在虚拟现实环境中导航的迅猛收获蚁（Cataglyphis velox）的运动行为，并在闭环和开环条件下，测量了它们对各种陌生视觉场景做出的横向摆动。在看似自然的全景中，蚂蚁会像在户外观察到的那样呈现出有规律的摆动，从而能够有效地扫视周围的景物。对虚拟环境的操控揭示了动态和静态线索所发挥的不同作用。动态线索，主要是旋转光流，调节了摆动的幅度，但对其规律性并无影响。相反，静态线索对幅度影响不大，但对于产生有规律的摆动至关重要。在仅有水平边缘、仅有垂直边缘或没有边缘的场景中，摆动的规律性会降低，但在同时具有两种边缘类型的场景中又会恢复。边缘的实际数量、方位上的视觉图案异质性、光强度或较亮区域的相对高度均不影响摆动。我们得出结论，蚂蚁依靠场景中至少存在两种不同的边缘方向，运用一种简单却有效的启发式方法来判断视觉世界是否值得探索。
