title: On the Encoding of Panoramic Visual Scenes in Navigating Wood Ants.
abstract: A natural visual panorama is a complex stimulus formed of many component shapes. It gives an animal a sense of place and supplies guiding signals for controlling the animal's direction of travel [1]. Insects with their economical neural processing [2] are good subjects for analyzing the encoding and memory of such scenes [3-5]. Honeybees [6] and ants [7, 8] foraging from their nest can follow habitual routes guided only by visual cues within a natural panorama. Here, we analyze the headings that ants adopt when a familiar panorama composed of two or three shapes is manipulated by removing a shape or by replacing training shapes with unfamiliar ones. We show that (1) ants recognize a component shape not only through its particular visual features, but also by its spatial relation to other shapes in the scene, and that (2) each segmented shape [9] contributes its own directional signal to generating the ant's chosen heading. We found earlier that ants trained to a feeder placed to one side of a single shape [10] and tested with shapes of different widths learn the retinal position of the training shape's center of mass (CoM) [11, 12] when heading toward the feeder. They then guide themselves by placing the shape's CoM in the remembered retinal position [10]. This use of CoM in a one-shape panorama combined with the results here suggests that the ants' memory of a multi-shape panorama comprises the retinal positions of the horizontal CoMs of each major component shape within the scene, bolstered by local descriptors of that shape.
authors.affiliation: School of Life Sciences, University of Sussex, John Maynard Smith Building, Brighton BN1 9QG, UK. Electronic address: cornelia.buehlmann@gmail.com.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Buehlmann
authors.affiliation: School of Life Sciences, University of Sussex, John Maynard Smith Building, Brighton BN1 9QG, UK. Electronic address: j.woodgate@qmul.ac.uk.
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Woodgate
authors.affiliation: School of Life Sciences, University of Sussex, John Maynard Smith Building, Brighton BN1 9QG, UK. Electronic address: t.s.collett@sussex.ac.uk.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Collett
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D003463:Cues; D008568:Memory; D000072458:Orientation, Spatial; D021641:Recognition, Psychology