Effects of natural mating and CO2 narcosis on biogenic amine receptor gene expression in the ovaries and brain of queen honey bees, Apis mellifera

A queen honey bee mates at ~6 days of age, storing the sperm in her spermatheca for life. Mating is associated with profound changes in the behaviour and physiology of the queen but the mechanisms underlying these changes are poorly understood. What is known is that the presence of semen in the oviducts and spermatheca is insufficient to initiate laying, and that copulation or CO2 narcosis is necessary for ovary activation. In this study we use real-time quantitative PCR to investigate the expression of biogenic amine receptor genes in the brain and ovarian tissue of queens in relation to their reproductive status. We show that dopamine, octopamine and serotonin receptor genes are expressed in the ovaries of queens, and that natural mating, CO2 narcosis, and the presence of semen in the spermatheca differentially affect their expression. We suggest that these changes may be central to the hormonal cascades that are necessary to initiate oogenesis.