We performed the following experiment to investigate whether contextual cues can prevent interference during the acquisition of potentially competing visuomotor associations in the bumble-bee (Bombus terrestris). Bees discriminated between horizontally and vertically orientated gratings of black and white stripes in order to reach a feeder and between di¡erent diagonally orientated gratings to gain access to their nest. Once bees were well trained on these two tasks, the discrimination task at the nest was changed so that bees had to distinguish between horizontal and vertical gratings at both sites. Whereas they still approached the horizontal grating to reach food, they now had to approach a vertical grating in order to return to their nest. The new task was learnt rapidly. Errors at the feeder did not increase during or after the acquisition of this potentially competing behaviour at the nest entrance. For a brief period during acquisition, bees showed some hesitation at the feeder and hovered for slightly longer before choosing between horizontals and verticals. After acquisition was complete, bees showed a slight increase in their preference for verticals over a more ambiguous stimulus of an array of dots. These ¢ndings are consistent with the hypothesis that di¡erent contextual signals are associated with approaching the nest or approaching the feeder, and that these contextual signals facilitate learnt associations between orientation detectors and motor commands.

Bees navigating between their nests and foraging sites rely on their ability to learn and to recall many complex visual patterns [1-4]. How are the elements that make up one of these patterns bound together so that the whole pattern can be recalled when it is required? Consider the sentence: 'Dons nod off.' The words in it can be distinguished by the pattern of elements or letters that they contain. Words may contain the same elements arranged in different orders (don, nod), or contain elements of different types, or vary in both these respects (nod, off). We show here that bumblebees (Bombus terrestris) can learn to group the elements of a pattern together, such that different identifiable patterns contain the same elements in different combinations--analogous to the grouping of letters found in words. Our results suggest that pattern binding in bees is achieved in part by linking pattern elements directly together and in part by associating the elements with cues that are related to the context in which the pattern is seen.

SUMMARY Bumblebees will learn to approach one of a pair of patterns (a 45°grating) and to avoid the other (a 135° grating) to reach a feeder, and to do the opposite to reach their nest (approach a 135° grating and avoid a 45° grating). These two potentially competing visuo-motor associations are insulated from each other because they are set in different contexts. We investigated what training conditions allow the two sets of associations to be acquired without mutual interference. If the discrimination at the feeder has already been learnt, then the discrimination at the nest can be readily acquired without disrupting the bees' performance at the feeder. But, if the two are learnt simultaneously,there is mutual interference. Prior experience of the two contexts before the discriminations are learnt does not prevent interference. We conclude that visual patterns and contextual cues must already be associated with each other for a visuo-motor association to be isolated from the interfering effects of a competing association that is acquired in a separate context. This pattern of results was mimicked in a simple neural network with Hebbian synapses, in which local and contextual cues were bound together into a configural unit.