The binding of visual patterns in bumblebees

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.