Species-specific differences in the fine structure of learning walk elements inCataglyphisants

Abstract

Cataglyphis desert ants are famous navigators. Like all central place foragers, they are confronted with the challenge to return home, i.e. relocate an inconspicuous nest entrance in the ground, after their extensive foraging trips. When leaving the underground nest for the first time, desert ants perform a striking behavior, so-called learning walks that are well structured. However, it is still unclear how the ants initially acquire the information needed for sky-and landmark-based navigation, in particular how they calibrate their compass system at the beginning of their foraging careers. Using high-speed video analyses, we show that different Cataglyphis species include different types of characteristic turns in their learning walks. Pirouettes are full or partial rotations (tight turns about the vertical body axis) during which the ants frequently stop and gaze back in the direction of the nest entrance during the longest stopping phases. In contrast, voltes are small walked circles without directed stopping phases. Interestingly, only Cataglyphis ant species living in a cluttered, and therefore visually rich, environment (i.e. C. noda and C. aenescens in southern Greece) perform both voltes and pirouettes. They look back to the nest entrance during pirouettes, most probably to take snapshots of the surroundings. In contrast, C. fortis inhabiting featureless saltpans in Tunisia perform only voltes and do not stop during these turns to gaze back at the nest -even if a set of artificial landmarks surrounds the nest entrance.

Principles of Insect Path Integration

“…After leaving the nest, flying insects turn back and move in a series of arcs centered around the nest, gradually gaining distance and elevation, while ensuring the nest is always seen in the left or right visual field. Walking insects, such as ants, engage in learning walks where they carry out multiple loops that begin and end at the nest [20,49,51]. During these loops, ants systematically turn back and look towards the nest.…”

Vector calibration in Australian desert ants, Melophorus bagoti: Effects of a delay after the acquisition of vector information

“…Upon release in the test ring or at the displacement site, the tested ants typically paused near the centre of the goniometer and scanned the surrounding environment, often making body saccades called pirouettes (in Cataglyphis noda : Fleischmann, Grob, Wehner, & Rössler, ; Freas et al, ; in M. bagoti : Wystrach, Philippides, Aurejac, Cheng, & Graham, ). Then, the ant would walk off directly in one direction.…”

Kompass im Kopf

“…Dabei entfernen sie sich immer weiter vom Nesteingang. Lernläufe enthalten unterschiedliche, artspezifische Drehungen, sogenannte ▸ Volten und ▸ Pirouetten, die wir mittels Highspeed‐Kameras genau untersucht haben . Lernläufe von Ameisen ähneln in ihrer Struktur und Funktion Lernflügen von Wespen und Bienen .…”

“…Die Ameisen unterbrechen ihre Vorwärtsbewegung oftmals, um Körperdrehungen auszuführen. Es gibt zwei unterschiedliche Drehungstypen, sogenannte Volten und Pirouetten . Bei einer Volte verlässt die Ameise ihren Pfad, um eine kleine 360°‐Schleife zu laufen, und dann in die ursprüngliche Richtung weiterzugehen.…”

“…Während der Volten gibt es hingegen keine zum Nest gerichteten Stoppphasen. Abbildung verändert aus .…”