Aggressive conflict as a transient and distributed landmark in homing desert ants

Across many species of the animal kingdom, the ability to navigate long distances is important for securing food and other resources. For example, ants, bees, and rats have long been known to use path integration, a mechanism to integrate distance and direction travelled, to find their way back to their nest. However, path integration is imperfect, and errors accumulate over time as animals forage. There are several ways to counteract this uncertainty, for example by utilizing local olfactory or visual landmarks along a familiar route to infer an individuals position relative to its nest, i.e. its homing vector. Local landmarks are thought to be effective if they are constant, granting a strong association with the discrete location it is located at. Here we show that ants can utilize something much sparser and more distributed than an individual constant landmark to inform its homing vector. Our data suggests that Tunisian desert ants integrate intraspecific contact, or social cues, to augment navigation. We demonstrate that contact with foreign conspecifics at a position where the nest is expected diminishes path integration certainty, thereby expanding the nest search pattern. Furthermore, we show that ants form associations between intraspecific conflict and discrete locations to create so called local vectors, within which the homing path to the nest can be stored. Highlights- Contact with foreign ants reduces path integrator certainty and alters homing strategy - Pattern of systematic search could be altered by persistent adaptions of walking speed - Foraging ants can form local vector memories using intraspecific conflict as a landmark