Investigating the Impact of Various Carbohydrates on the Longevity and Physiological Traits of Honeybees

Carbohydrates play a crucial role as a primary energy source for honeybees, influencing their overall fitness and resilience. Given the potential implications for colony dynamics, foraging efficiency, and long-term survival, it is imperative to analyze the effects of various carbohydrates on honeybees. This study aimed to investigate the impact of diverse carbohydrate sources on honeybee longevity. Newly emerged honeybees were provided with a range of carbohydrates, including white sugar, brown sugar, corn syrup, maltose, acacia honey, chestnut honey, and oligosaccharide at libitum, and their effect on honeybee longevity, size of hypopharyngeal glands, relative expression of ilp1, ilp2, and vg genes and the composition of honey bee gut microbiome were evaluated. Results revealed significant disparities in honeybee longevity, with the group fed corn syrup exhibiting the highest longevity, followed by acacia honey and white sugar syrup. Conversely, the group consuming oligosaccharide demonstrated the lowest longevity. Our research further explores the physiological and metabolic effects of different carbohydrate sources on honey bees. Bees fed corn syrup demonstrated significant development of hypopharyngeal glands, correlating with improved survival and longevity. Gene expression analysis revealed that corn syrup influenced insulin-like peptide (Ilp) levels, with Ilp1 expression being lower and Ilp2 expression higher in older bees, aligning with increased longevity. Additionally, shifts in gut microbiota were observed, with an increase in less dominant bacteria like Frischella and Rhizobiaceae (Bartonella), which may play a role in compensating for the lack of essential amino acids in the bees' diet. These findings underscore the complexity of honey bee nutrition, emphasizing the importance of balanced carbohydrate sources that cater to the bees' metabolic needs and support their overall health. The study highlights the potential of corn syrup as a viable alternative to traditional carbohydrate sources, offering insights for optimizing honey bee management and conservation strategies. Further research is needed to unravel the detailed mechanisms driving these nutritional interactions and their implications for colony health and resilience.