Naturalistic path integration of Cataglyphis desert ants on an air-cushioned lightweight spherical treadmill

Abstract

Air-cushioned spheres are widely used as treadmills to study behavioural and neurophysiological questions in numerous species. We describe an improved spherical treadmill design that reliably registers the path and walking behaviour of an animal walking on top of the sphere. The simple and robust set-up consists of a very light hollowed styrofoam ball supported by an air stream in a hollow half sphere and can be used indoors and outdoors. Two optical mouse sensors provided with lenses of 4.6 mm focal length detect the motion of the sphere with a temporal resolution of more than 200 frames sand a spatial resolution of less than 0.2 mm. The treadmill can be used in an open-or closed-loop configuration with respect to yaw of the animal. The tethering allows animals to freely adjust their body posture and in the closed-loop configuration to quickly rotate around their yaw axis with their own moment of inertia. In this account, we present the first evidence of naturalistic homing navigation on a spherical treadmill for two species of Cataglyphis desert ants. We were able to evaluate with good precision the walking speed and angular orientation at any time. During homing the ants showed a significant difference in walking speed between the approach and search phases; moreover, they slowed down significantly as soon as they reached zero vector state, the fictive nest position.

A Neurocomputational Model of Goal-Directed Navigation in Insect-Inspired Artificial Agents

“…Such neural representations have yet to be observed in experiments, ideally by applying the tethered track ball setup described in Seelig and Jayaraman (2015). A recent study has developed such a system for the use in desert ants (Dahmen et al, 2017), providing a powerful tool for future investigation of underlying neuronal mechanisms by combining this technology with electrophysiological recordings.…”

Animals in Virtual Environments

“…Arena, Projection Optical Tracking, Active treadmill Fruit fly -Real-time 3D tracking [32], vision induced motion [72], Flight pattern [73] Spider -Navigation [64,72], Ant -Foraging [18], Fish -Social behavior [73], Rodent- [20,73], Review -Neuroscience [8,27], VR for animals [72], Rodent - [80] Free moving animals, real time perspective correction, underwater projection, arbitrary surfaced arena, support for multiple species, configurable software. authors claimed that they were able to study depth perception in fruit flies with the system which was not possible in previously designed open-loop methods.…”

“…This type of design facilitates behavior studies without creating very large arenas e.g. navigation behavior in jumping spider [65] [72] or foraging behavior in desert ants [18]. Treadmill-based solutions are not suitable for all animals and therefore the development of novel 3D tracking methods was crucial for the development of VR solutions for animals.…”

“…Additionally, the rotation mechanism of the ball must sensitive towards variations in the movement of the animal. For example, the ball must accelerate and decelerate in sync with the animals motion otherwise it may create an unwanted perturbation for the animal [18]. Similar considerations must be made when selecting cameras for tracking motion of the animal in tethered cases.…”

An autonomous robot for continuous tracking of millimetric-sized walkers

“…The work of H. Dahmen et al 7 stands out as an example of mobile region procedures applied to insect tracking. The instrument consists of an air-cushioned lightweight spherical treadmill that registers the path of an animal a) gvieralopez@fisica.uh.cu walking on top of the sphere.…”