title: Subtle changes in the landmark panorama disrupt visual navigation in a nocturnal bull ant.
abstract: The ability of ants to navigate when the visual landmark information is altered has often been tested by creating large and artificial discrepancies in their visual environment. Here, we had an opportunity to slightly modify the natural visual environment around the nest of the nocturnal bull antMyrmecia pyriformisWe achieved this by felling three dead trees, two located along the typical route followed by the foragers of that particular nest and one in a direction perpendicular to their foraging direction. An image difference analysis showed that the change in the overall panorama following the removal of these trees was relatively little. We filmed the behaviour of ants close to the nest and tracked their entire paths, both before and after the trees were removed. We found that immediately after the trees were removed, ants walked slower and were less directed. Their foraging success decreased and they looked around more, including turning back to look towards the nest. We document how their behaviour changed over subsequent nights and discuss how the ants may detect and respond to a modified visual environment in the evening twilight period.This article is part of the themed issue 'Vision in dim light'.
authors.affiliation: Department of Biological Sciences, Macquarie University, 205 Culloden Road, Sydney, New South Wales 2109, Australia ajay.narendra@mq.edu.au.
authors.forename: Ajay
authors.identifier: http://orcid.org/0000-0002-1286-5373
authors.initials: A
authors.lastname: Narendra
authors.affiliation: Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Fiorella
authors.identifier: http://orcid.org/0000-0003-3995-9422
authors.initials: F
authors.lastname: Ramirez-Esquivel
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D003463:Cues; D003624:Darkness; D000072458:Orientation, Spatial; D014796:Visual Perception
keywords: Myrmecia; learning walks; night-active; panorama; visual navigation