Modulation of brain dopamine levels in East Asian honey bee (Apis cerana) workers from queenless and queenright colonies.

Abstract

This study aimed to determine the effect of queen bee in lowering the brain dopamine levels of Apis cerana worker bees, thus affecting their locomotor activity and attraction to queen bee, by virtue of the pheromones she emits. Two behavioral assays and measurement of brain dopamine levels by high performance liquid chromatography were conducted on 1-day old to 7-day old worker bees, from queenright and queenless colonies. In the first behavioral assay, evaluation of locomotor activity, it was found out that motor activity increased with age, in both queenright and queenless colonies. The 7-day old bees are the most mobile and the 1-day old bees are the least mobile. In the second behavioral assay, measurement of attraction to queen, it was observed that queenright worker bees were more attracted to the queen than queenless workers. Moreover, 2-day old to 5-day old bees are the most attracted to the queen. Finally, the dopamine level measurement showed that worker bees from queenright colonies had lower dopamine levels than worker bees from queenless colonies, with no significant differences among varying ages. It was concluded that the presence of the queen bee has a profound impact on the behavior and physiology of 1-day old to 7-day old worker bees through the modulation of brain dopamine levels. Lower dopamine levels of the workers allow the queen to control the behavior of the worker bees, allowing them to fulfill their roles in the colony.