How does invert sugar syrup affect sealed worker brood and colony strength in Roger-Delon hives?

Honeybees are the most valuable pollinators for ecosystems. This study aimed to determine the effects of inverted sugar syrup on the sealed worker brood and colony strength in Roger-Delon hives. The study was conducted in 2024, involving 14 Roger-Delon hives. The experiment was conducted at an altitude of 860 meters in the area of the town of Tran, Pernik region. Bee colonies were assigned to two treatment groups: inverted sugar syrup supplementation (experimental group with 7 bee colonies) and supplementation with sugar solution (control group with 7 bee colonies), at a rate of 250 ml per colony twice a week. In the present experiment with Roger-Delon hives, the bee colonies supplemented with inverted sugar syrup had significantly higher average values of sealed worker brood and colony strength, than those in the control group (p<0.001), following spring and autumn feedings. These results confirm that inverted sugar syrup is more effective supplemental feed for improving brood production in honeybee colonies, probably due to its higher digestibility. Further studies are needed over longer periods of time, as they could provide a deeper insight into the long-term effects of inverted sugar syrup on bee colony growth and productivity in Roger-Delon hives.