Caste-specific nutritional signatures: Comparative physicochemical characterization of royal, worker, and drone jelly and larvae across developmental stages in Apis mellifera L.

Differentiation between honey bee castes is essentially a nutritional phenotype, but the complex physicochemical inputs that play critical roles in endocrine and epigenetic programming are still poorly documented, particularly for worker jelly (WJ) and drone jelly (DJ), which are rarely characterized alongside royal jelly (RJ) and the larvae that metabolize them. Here, we compare RJ, WJ and DJ and queen (1-4 d), worker (1-5 d) and drone (1-6 d) larvae produced under standardized field conditions (15 colonies) in Ordu, Türkiye (18 biological groups) systematically with respect to caste and age. Moisture/dry matter and ash were determined gravimetrically, protein by Dumas combustion, sugars and 10-hydroxy-2-decenoic acid (10-HDA) using HPLC (RID/UV), minerals and heavy metals by ICP-MS, and acidity based on pH and titration. RJ complied with international composition standards: protein (12.90%) and 10-HDA content at the authenticity threshold (1.41%). WJ exhibited elevated protein (16.80%) and the highest titratable acidity (48 mL 1 N NaOH/100 g), alongside relatively enriched macro- and microelement profiles, particularly K and Mg, providing a distinguishing nutritional "signature" of larval foods; DJ showed the highest protein density of all matrices (18.37%). Sugar profiles suggested that glucose and fructose predominated, but a strong developmental pattern for sucrose became clear: large amounts of sucrose were present in 1-day-old larvae but absent from all later developmental stages, consistent with rapid turnover of the carbohydrate pool during early growth. RJ was the most acidic matrix (pH 3.96), and pH increased with larval age across castes suggesting buffering, tissue growth and remodelling in the context of aligned biomass accumulation. Together, these data establish comparative baseline datasets for caste-related larval foods and larvae, reinforce authenticity quality-control frameworks beyond RJ alone, and furnish a physicochemical basis for mechanistic studies linking food chemistry with caste-linked developmental physiology. These baseline data also offer practical reference points for veterinary monitoring of larval nutrition and colony health. Beyond providing a comprehensive reference dataset, the divergent nutritional profiles we observed particularly in protein, sugar, and 10-HDA dynamics suggest that the temporal coordination of these components may contribute to the canalization of caste-specific developmental pathways.