title: Head movements and the optic flow generated during the learning flights of bumblebees.
abstract: Insects inform themselves about the 3D structure of their surroundings through motion parallax. During flight, they often simplify this task by minimising rotational image movement. Coordinated head and body movements generate rapid shifts of gaze separated by periods of almost zero rotational movement, during which the distance of objects from the insect can be estimated through pure translational optic flow. This saccadic strategy is less appropriate for assessing the distance between objects. Bees and wasps face this problem when learning the position of their nest-hole relative to objects close to it. They acquire the necessary information during specialised flights performed on leaving the nest. Here, we show that the bumblebee's saccadic strategy differs from other reported cases. In the fixations between saccades, a bumblebee's head continues to turn slowly, generating rotational flow. At specific points in learning flights these imperfect fixations generate a form of 'pivoting parallax', which is centred on the nest and enhances the visibility of features near the nest. Bumblebees may thus utilize an alternative form of motion parallax to that delivered by the standard 'saccade and fixate' strategy in which residual rotational flow plays a role in assessing the distances of objects from a focal point of interest.
authors: Centre for Computational Neuroscience and Robotics, Department of Informatics, University of Sussex, Brighton BN1 9QJ, UK.
authors: Olena
authors: O
authors: Riabinina
authors: Psychology, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK.
authors: Natalie Hempel
authors: NH
authors: de Ibarra
authors: Centre for Computational Neuroscience and Robotics, Department of Informatics, University of Sussex, Brighton BN1 9QJ, UK.
authors: Andrew
authors: A
authors: Philippides
authors: School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK t.s.collett@sussex.ac.uk.
authors: Thomas S
authors: TS
authors: Collett
mesh_terms: D000818:Animals; D001516:Bees / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology*; D019416:Head Movements; D007858:Learning / Q000502:physiology*; D009068:Movement; D057849:Optic Flow / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D012438:Saccades / Q000502:physiology; D013028:Space Perception / Q000502:physiology
keywords: Active vision; Insect navigation; Motion parallax; Pivoting parallax; Saccades; Visual learning