How bumblebees coordinate path integration and body orientation at the start of their first learning flight

Abstract

AbstractThe start of a bumblebee’s first learning flight from its nest provides an opportunity to examine the bee’s learning behaviour on its initial view of the nest’s unfamiliar surroundings. Bumblebees like many other ants, bees and wasps learn views of their nest surroundings while facing their nest. A bumblebee’s first fixation of the nest is a coordinated manoeuvre in which the insect faces the nest with its body oriented towards a particular visual feature within its surroundings. The manoeuvre’s utility is that during return flights after foraging bees, when close to the nest, adopt the same preferred body-orientation (Hempel de Ibarra et al., 2009; Robert et al., 2018). A translational scan oriented orthogonally to the bee’s body-orientation helps the bee reach the preferred conjunction of nest-fixation and body-orientation.How does a bee, unacquainted with its surroundings, know when it is facing its nest? The details of nest-fixation argue that, like desert ants (Fleischmann et al., 2018), the bee relies on path integration. Path integration gives bees continuously updated information about the current direction of their nest and enables them to fixate the nest when the body points in the appropriate direction. We relate the three components of the coordinated manoeuvre to events in the central complex, noting that nest fixation is in egocentric coordinates, whereas body orientation and flight direction within the visual surroundings of the nest are in geocentric coordinates.