Biogenic amines and division of labor in honey bee colonies

Brain levels of dopamine, serotonin, and octopamine were measured in relati on to both age-related division of labor and inter-individual differences i n task specialization independent of age in honey bee colonies. The only di fferences among similarly aged bees performing different tasks were signifi cantly lower levels of dopamine in food storers than comb builders and sign ificantly lower levels of octopamine in soldiers than foragers, but soldier s also were slightly younger than foragers. Differences associated with age -related division of labor were stronger. Older bees, notably foragers, had significantly higher levels of all three amines than did younger bees work ing in the hive. Using social manipulations to unlink chronological age and behavioral status, octopamine was found to exhibit the most robust associa tion between behavior and amine level, independent of age. Octopamine level s were significantly lower in normal-age nurses versus precocious foragers and overage nurses versus normal-age foragers, but not different in reverte d nurses versus reversion colony foragers. Dopamine levels were significant ly lower in normal-age nurses versus precocious foragers, but higher in rev erted nurses versus reversion colony foragers. Serotonin levels did not dif fer in any of these comparisons. These correlative results suggest that oct opamine is involved in the regulation of age-related division of labor in h oney bees.