Brain biogenic amines and reproductive dominance in bumble bees (Bombus terrestris)

To begin to explore the role of biogenic amines in reproductive division of labor in social insects, brain levels of dopamine, serotonin, and octopami ne were measured in bumble bee (Bombus terrestris) workers and queens that differ in behavioral and reproductive state. Levels of all three amines wer e similar for mated and virgin queens. Young workers that developed with or without a queen had similar amine levels, but in queenright colonies diffe rences in biogenic amine levels were associated with differences in behavio r and reproductive physiology. Dominant workers had significantly higher oc topamine levels compared with workers of lower dominance status but of simi lar size, age, and ovary state. High dopamine levels were associated with t he last stages of oocyte development irrespective of worker social status a nd behavior. These results suggest that biogenic amines are involved in beh avioral and physiological aspects of regulation of reproduction in bumble b ees.