Morphometric and Biochemical Parameters of Apis mellifera Workers Fed on Protein Supplement

Nutrition is one of the main challenges facing honey bees, especially during autumn and winter. This work aimed to evaluate the effects of feeding Apis mellifera with a protein-enriched diet (YCPC) compared to a control diet. Development of the hypopharyngeal glands (HPGs), dimensions of the second wax mirror, and the stinging apparatus were measured in the two groups. Additionally, key biochemical parameters were assessed in homogenized worker honey bees. No significant differences were observed in hypopharyngeal gland (HPG), acini diameters or surface area, or in the measurement of the stinging apparatus and poison sac, except for a slight decrease in the newly emerged bees. YCPC supplementation significantly elevated total soluble protein content in newly emerged and nurse bees. Lower lipid levels were observed in newly emerged and nurse bees from the supplemented group and higher lipid reserves in were observed in supplemented foragers. No significant variation was observed in total carbohydrate content, except for a significant reduction in supplemented newly emerged bees. Acetyl cholinesterase activity was higher in younger bees and lower in foragers. A slight elevation in α and β-esterase expression was detected in the supplemented group, supporting enhanced detoxification capacity. YCPC enhances the biochemical capacity of honey bees, particularly in the early adult stages. However, glandular and morphological development were not affected.