Assessing the physiological impacts of different invert sugars and sucrose on caged nurse honey bees

The quantity and type of carbohydrate sources applied in supplemental feeding have a substantial impact on honey bee physiology and overall colony health. This study examined five carbohydrate treatments—sucrose, Invertase-hydrolysed inverted sugar, Acid-hydrolysed inverted sugar, Algae-derived inverted sugar and honey as a control. Their effects on syrup consumption, rectal weight, lactic acid level, and survival were studied using caged bees under laboratory conditions. Caged bees provided with sucrose had the best results, with high survival rates, lower rectal weights, and minimum lactic acid accumulation, reflecting efficient digestion and a stable gut microbiome. Bees fed algae-derived sugar, on the other hand, died at a high rate and had raised levels of rectal weight and lactic acid, indicating changes in gut microbial composition and abnormal fermentation. Acid-inverted sugar was poorly consumed, possibly due to limited palatability, and led to adverse physiological changes. Enzyme-inverted sugar and honey exhibited balanced reactions, with moderate fermentation indications and adequate syrup consumption. These preliminary findings demonstrate the potential impact of carbohydrate composition and processing methods on honey bee digestive health. Sucrose remains the most appropriate artificial sugar, whereas non-traditional sources, particularly algae-based syrups, may have negative physiological effects.