Previous research showed that age-related division of labor in honey bees is associated with changes in activity rhythms; young adult bees perform hive tasks with no daily rhythms, while older bees forage with strong daily rhythms. We report that this division of labor also is associated with differences in both circadian rhythms and mRNA levels of period, a gene well known for its role in circadian rhythms. The level of period mRNA in the brain oscillated in bees of all ages but was significantly higher in foragers. This cannot be attributed exclusively to aging, because bees induced to forage precociously due to a change in social environment also had elevated period brain mRNA. These results constitute the first report of the regulation of a clock gene in a social context and suggest that there are molecular level connections between division of labor and chronobiology in social insects.

Representative Publications

Bloch G, Toma DP, Robinson G (2001) Behavioral rhythmicity, age, division of labor and period expression in the honey bee brain. J. Biol. Rhythm 16: 444-456. (pdf)

Bloch, G. and G.E. Robinson (2001) Socially mediated plasticity in honeybee behavioural rhythms. Nature 410:1048. (pdf)

Toma DP, Bloch G, Moore D, Robinson GE (2000) Changes in period mRNA levels in the brain and division of labor in honey bee colonies. Proc. Natl. Acad. Sci. USA 97:6914-6919. (pdf)