The use of geometric information in spatial navigation of bumblebees

Human and non-human animals are capable to make use of geometric information (metric and sense) specified by the macroscopic layout of surfaces to reorient in an environment. It is debated, however, whether geometric information is encoded by explicitly computing the layout of surface geometry of by matching images of the environment. View-based spatial encoding is generally thought to hold for insect navigation and, very recently, evidence for navigation by geometry in ants has been reported. Here we tested bumblebees (Bombus terrestris) abilities for spatial reorientation. After spatial disorientation, by passive rotation both clockwise and anticlockwise, bumblebees had to find one of the four exit holes located in the corners of a rectangular enclosure. Bumblebees systematically confused geometrically equivalent exit corners (i.e. corners with the same geometric arrangement of metric properties and sense). When one wall of the enclosure was made of a different colour, bumblebees conjoined this featural information with geometry to find the uniquely correct exit corner even when located on a different wall with respect to the goal corner. Our results show that bumblebees are able to use both geometric and featural information to reorient themselves, with similar behaviour as shown by vertebrates under similar conditions of testing.