| Many organisms live as part of complex societies. As these organisms mature, they pass through many developmental and physiological stages mediated by social interactions.; Honey bees are highly social animals that display a complex pattern of behavioral development. Adult worker bees change jobs as they age, which gives rise to an age-related division of labor in honey bee colonies, a key feature in the organization of honey bee society.1 Young adult honey bees perform hive tasks with no daily rhythms, while older bees forage with strong daily rhythms.2; These results suggest that multiple aspects of honey bee behavior are related to a clock mechanism. I report that honey bee division of labor is associated with striking differences in the expression of a major circadian clock gene, period (per), which has been shown to be involved in several temporal aspects of the life of the fruit fly, Drosophila melanogaster.3 Per mRNA levels in the brain oscillate in bees of all ages but are significantly higher in foragers. This is not a consequence of aging, because bees induced to forage precociously due to a change in social environment also have elevated period brain mRNA. This is the first report of the regulation of clock gene mRNA levels in a social context.; In addition, I report analyses of the complete cDNA sequence and the complete genomic sequence within the coding region for per from the honey bee. Honey bee per cDNA has significant structural similarity to per in both insects and mammals. In addition, bee-fly comparisons of intron positions reveal many unique insertions in the bee genomic sequence, supporting the "introns late" hypothesis.; 1Winston, M. L. (1987) The Biology of the Honey Bee. Harvard University Press, Cambridge, MA. 2Moore, D., J. E. Angel, I. M. Cheeseman, S. E. Fahrbach, and G. E. Robinson. (1998) Behav. Ecol. Sociobiol. 43: 147--160. 3Hall, J. C. (1995). TINS 18: 230--240. |
