Comparative analysis of dopamine levels and related gene expression in the brains of honeybee (Apis mellifera) workers of different ages

Author of the article:ZENG Zhao-Yang** ZHANG Hang-Yu** PU Shu-Ting WU Zun LI Lin-Feng CHEN Zhuo SU Song-Kun*** XU Xue-Ling***

Author's Workplace：College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China

Key Words：Apis mellifera; dopamine; day-old; synthesis; receptor

Abstract：[Aim] To clarify dynamic changes in the dopamine content, and related gene activity, in the brain of worker honeybees (Apis mellifera) of different ages under natural conditions. [Methods] High-performance liquid chromatography-electrochemical detection (HPLC-ECD) was used to determine the dopamine content of the brains of 1, 5, 10, 15, 20, 25, and 30-day-old, worker honeybees from normal colonies. Quantitative real-time polymerase chain reaction (qRT-PCR) technology was used to detect the relative expression levels of the dopamine synthesis genes (Th and Ddc) and the dopamine receptor genes (Amdop1, Amdop2, Amdop3), in order to construct an age-specific profile of dopamine content and gene expression. [Results] Dopamine levels in the brain underwent age-specific changes. Dopamine levels were relatively high in 1-day-old workers, after which they decreased before rising significantly (P < 0.001) in 20-day-old bees (the critical period when workers shift to foraging behavior), then declining again. The expression of the Th gene was highest in the brains of 1-day-old workers and remained relatively stable with age. The expression levels of Amdop1, Amdop2, and Amdop3 were low in 1-day-old workers and were generally upregulated during subsequent developmental stages. Amdop2 was relatively highly expressed in 10, 15, and 20 day-olds. [Conclusion] These results not only provide key data for investigating the factors influencing changes in honeybee behavior, but also provide theoretical support for the association between neurotransmitters and behavior in social insects.