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The effect of step size on straight-line orientation

  • Lana Khaldy
  • Orit Peleg
  • Claudia Tocco
  • L. Mahadevan
  • Marcus Byrne
  • Marie Dacke
Publishing year: 2019
Language: English
Publication/Series: Journal of the Royal Society, Interface
Volume: 16
Issue: 157
Document type: Journal article
Publisher: The Royal Society of Canada

Abstract english

Moving along a straight path is a surprisingly difficult task. This is because, with each ensuing step, noise is generated in the motor and sensory systems, causing the animal to deviate from its intended route. When relying solely on internal sensory information to correct for this noise, the directional error generated with each stride accumulates, ultimately leading to a curved path. In contrast, external compass cues effectively allow the animal to correct for errors in its bearing. Here, we studied straight-line orientation in two different sized dung beetles. This allowed us to characterize and model the size of the directional error generated with each step, in the absence of external visual compass cues (motor error) as well as in the presence of these cues (compass and motor errors). In addition, we model how dung beetles balance the influence of internal and external orientation cues as they orient along straight paths under the open sky. We conclude that the directional error that unavoidably accumulates as the beetle travels is inversely proportional to the step size of the insect, and that both beetle species weigh the two sources of directional information in a similar fashion.


  • Evolutionary Biology
  • compass
  • dung beetle
  • navigation
  • orientation
  • random walk
  • step size


  • Lund Vision Group
  • ISSN: 1742-5662
Marie Dacke
E-mail: marie [dot] dacke [at] biol [dot] lu [dot] se


Functional zoology

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