ELEVATED BRAIN DOPAMINE LEVELS ASSOCIATED WITH OVARY DEVELOPMENT IN QUEENLESS WORKER HONEY-BEES (APIS-MELLIFERA L)

Brain levels of octopamine (OA), dopamine (DA) and serotonin (5HT) were compared between worker honey bees (Apis mellifera L.) kept with or without queens in various experiments. Levels of DA were significantly higher in queenless bees than in their sisters that had been kept with queens either (1) in small field colonies for 30 days or (2) in incubator cages through 18 days. This difference was not observed in a separate incubator experiment after 6 and 12 days. A correlation between ovariole width and brain DA levels was found in groups of caged queenless workers after 18 days. In pairs of caged workers kept in an incubator through 10 days, the worker having the largest ovariole width was significantly more likely to have higher brain DA levels. The increased DA levels in queenless bees probably reflect changes in behavioral states that occur after onset of oogenesis.