Honey bee colonies operate as a highly organized superorganism, functioning as a single integrated organism rather than just a collection of individual bees [1,2]. Female honey bees have evolved into two distinct types: with queen is responsible for reproducing and propagating the colony's offspring, while the worker bee undertakes the daily tasks such as cleaning the hive, feeding the larvae, and collecting nectar and pollen [3,4]. The reproductive queen and the sterile workers are both developed from diploid fertilized eggs, with their genomes being similar, but the fate of developing into either the queen or the worker is primally regulated by the quantity and quality of royal jelly provided by nurse workers [5,6]. During the reproductive process, the queen firstly lay the eggs in the queen cell, the nurse bees then provide food to the larvae in the form of royal jelly, which is synthesized and secreted mainly by the worker bees' hypopharyngeal gland, mandibular gland, and salivary glands [7,8]. The quantity, quality and timing of royal jelly ingestion by the larvae determine their hormonal signals and epigenetic patterns, which lead to caste differentiation in honey bees [[9], [10], [11]]. All brood care in honey bee colonies is performed by nurse bees, who provide alloparent care to their sisters, raising female larvae mostly into new workers and sometimes into new queens [12]. The ability of nurse bees to produce and provide a sufficient quantity and quality of royal jelly is, therefore, an essential component of the reproductive investment in honey bees [13,14].

Royal jelly is rich in functional proteins that are crucial for human health [15]. To obtain high yields of royal jelly, China has selected a honey bee stock RJBs (high royal jelly producing bees) from ITBs (Italian bees, Apis mellifera ligustica) through more than 50 years of artificial selection [16,17]. This artificial selection not only increased the royal jelly yield, with RJBs could producing at least 10 times more royal jelly per colony per year than their ITBs counterparts, but also altered the associated social traits of colony, including increased queen cell acceptance, improved larval rearing, and enhanced pollen hoarding [[18], [19], [20]].

The molecular mechanism underlying the high royal jelly secretion of RJBs have been partially elucidate at single organ level since the successful selection of this bee stock [21]. High royal jelly production trait in RJBs is genetically inherited [22,23]. Compared to ITBs, the RJBs have morphological and signal pathways alterations in their hypopharyngeal gland, including larger acini, longer royal jelly secretion periods and enhanced protein synthesis and energy metabolism [[24], [25], [26]]. The mandibular gland, a major source of fatty acids in royal jelly, has enhanced lipid synthesis and transport in RJBs to maintain the lipid level required for larva development [27]. In RJB larvae, the amino acid metabolism and protein synthesis pathways in the hemolymph are also strengthened [28]. The neurobiology of RJBs has been reshaped, with enhanced signal transduction, energy and nutrient metabolic pathways in the central nervous system to sustain nerve sensitivity and brood signal processing [29]. Additionally, RJBs have shaped a strong water homeostasis to accommodate the elevated royal jelly secretion [30]. In the peripheral nervous system, the expression of odorant receptors in the antennae of RJBs is increased, which partially leads to a more sensitive response to larval pheromones, allowing the RJBs nurse bees to accept more larvae compare to ITBs [18].

Although the mechanisms of high royal jelly production have been extensively studied at the single organ, the knowledge of how multiple organs cooperate with each other to boost the elevated production in RJBs is still lacking. The aim of this study is to compare the proteome of the nervous system, glands for royal jelly secretion, digestive and excretory system, and nutrition supply system of nurse bees between ITBs and RJBs to identify key regulate organs or pathways responsible for high royal jelly production in RJBs. This will establish a systematic understanding of royal jelly production at the multi-organ proteome level.