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

Abstract

The start of a bumblebee's first learning flight from its nest provides an opportunity to examine the bee's learning behaviour during its initial view of the nest's unfamiliar surroundings. Bumblebees like many other bees, wasps and ants learn views of their nest surroundings while they face their nest. We find that 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. This conjunction of nest-fixation and body-orientation is preceded and reached by means of a translational scan during which the bee flies perpendicularly to its preferred body orientation. The significance of the coordinated manoeuvre is apparent during return flights after foraging. Bees then adopt a similar preferred body-orientation when they are close to the nest. How does a bee, unacquainted with its surroundings, know when it is facing its nest? A likely answer is path integration which gives bees continuously updated information about the current direction of their nest. Path integration also enables bees to fixate the nest when the body points in the appropriate direction. The three components of this coordinated manoeuvre are discussed in relation to current understanding of the central complex in the insect brain, noting that nest fixation is egocentric, whereas adopting a preferred body orientation and flight direction within the visual surroundings of the nest are geocentric.