Honey bees exhibit two complex social behaviors which have long fascinated human observers: the "dance language," a series of body movements whereby successful scout bees precisely communicate to their nestmates the locations of flowers as far away as 10 kilometers; and highly organized, perennial colonies. Little is known about how the behaviors we see in honey bees alive today emerged from the simpler capabilities of their solitary-living ancestors. Since behavior, unlike structure, is not fossilized, the historical sequences of changes cannot be observed directly. Instead, it must be inferred from comparisons of closely related living species. Since equivalent traits in related species can be assumed to have descended from a common ancestor, one can infer the characteristics of the ancestral trait, and the modifications that occurred during descent, from the similarities and differences seen among species now alive. There are 6-8 species of honey bees (genus Apis which all have dance languages, but which differ in the details of the dances. All the Apis species have advanced societies, but bees in other genera exhibit varying degrees of social organization. These patterns have already been used to formulate competing hypotheses about the evolution of these behaviors. Ambiguities remain because no set of independent traits has satisfactorily resolved the phylogenetic relationships among the honey bee species, and among the different bee genera. The present project will undertake the first comprehensive study of molecular variation among bees, though an analysis of sequences of nucleotides (subunits of the DNA molecule) in a gene found in all the species. Specimens will be collected in several locations in Asia and Central America, the gene extracted and sequenced, and the phylogenetic relationships among the species determined from variations in the sequences. At the same time, further detailed studies will be done to obtain a clearer picture of the pattern of behavioral variation among the species. Together these approaches should lead to more satisfying answers to two questions: how the dance was assembled from a set of simpler behaviors, and whether advanced sociality originated uniquely in honey bees or was derived from an ancestor which also gave rise to other highly social bees. Apart from leading to a better understanding of the biology of a fascinating and ecologically important group of organisms, this project will also provide a model for combining molecular and behavioral approaches to reconstruct the evolution of complex behavior in other animals. Additionally, the patterns of variation among different honey bee populations in Southeast Asia, which is fragmented into islands separated by a range of distances and for varying periods of time, could lead to insights into the processes governing the behavioral and genetic divergence of animal populations evolving in isolation. Finally, given the prominent role played by the honey bees in the pollination of trees in tropical forests, these studies could aid future attempts to understand the ecology of this important ecosystem.
