Landmarks or panoramas: what do navigating ants attend to for guidance?

Abstract

BackgroundInsects are known to rely on terrestrial landmarks for navigation. Landmarks are used to chart a route or pinpoint a goal. The distant panorama, however, is often thought not to guide navigation directly during a familiar journey, but to act as a contextual cue that primes the correct memory of the landmarks.ResultsWe provided Melophorus bagoti ants with a huge artificial landmark located right near the nest entrance to find out whether navigating ants focus on such a prominent visual landmark for homing guidance. When the landmark was displaced by small or large distances, ant routes were affected differently. Certain behaviours appeared inconsistent with the hypothesis that guidance was based on the landmark only. Instead, comparisons of panoramic images recorded on the field, encompassing both landmark and distal panorama, could explain most aspects of the ant behaviours.ConclusionAnts navigating along a familiar route do not focus on obvious landmarks or filter out distal panoramic cues, but appear to be guided by cues covering a large area of their panoramic visual field, including both landmarks and distal panorama. Using panoramic views seems an appropriate strategy to cope with the complexity of natural scenes and the poor resolution of insects' eyes. The ability to isolate landmarks from the rest of a scene may be beyond the capacity of animals that do not possess a dedicated object-perception visual stream like primates.

Comparative outlook over physiological and ecological characteristics of three closely-related Myrmica species

“…The latter species, nesting in visually rich environment, learn visual cues more efficiently. More recently, Wystrach et al (2011b) went a step further, somewhat modifying previous affirmations. They provided M. bagoti ants with a huge artificial landmark located right near the nest entrance to find out whether navigating ants focus on such a prominent visual landmark for homing guidance.…”

The forest or the trees: preference for global over local image processing is reversed by prior experience in honeybees

“…In the case of a moving animal, previous experience of successful visually guided foraging may render global information more robust to movement disturbance or variations in view angle, among other factors. Additionally, constructing a global landscape from local landmarks is an important navigation strategy for both bees and ants [32,[59][60][61]. Interestingly, arbitrating between local and global processing of the visual panorama, among other available cues [62][63][64], has revealed a crucial factor of navigation success [32,60].…”

Look up: Human adults use vertical height cues in reorientation

“…In this case, the geometric shape of the boundary of the environment formed by mountains could be used as an orienting cue. Indeed, the panoramic contour formed by the view of terrestrial objects against the skyline has been shown to be a potent navigational cue for foraging ants (e.g., Graham & Cheng, 2009;Legge, Wystrach, Spetch, & Cheng, 2014;Wystrach, Beugnon, & Cheng, 2011).…”