Impact of Comb Cell Diameter on Nectar Evaporation Efficiency in Honey Bees

Honey bees transform nectar into honey through a combination of physical and chemical processes, with the physical process primarily involving the evaporation of excess water to concentrate the nectar. However, the factors affecting evaporation efficiency, such as evaporation duration, cell type, and bee species, remain incompletely understood. This study aimed to examine how these factors affect nectar evaporation efficiency during honey production. We measured the sucrose content in solutions subjected to combined active and passive evaporation, as well as passive evaporation alone. The results showed that eastern honey bee (EHB; Apis cerana) colonies were more efficient at concentrating sucrose solutions in worker cells than in drone cells under both combined active and passive evaporation conditions, as well as passive evaporation alone. Conversely, western honey bee (WHB; Apis mellifera) colonies exhibited greater efficiency in drone cells. Additionally, EHB colonies were more effective than WHB colonies in converting sucrose into fructose and glucose. Under passive evaporation, EHB colonies required at least 48 h to significantly concentrate the sucrose solution, while WHB colonies achieved similar concentrations in just 24 h. Sucrose content increased with the duration of passive evaporation. These findings provide insights into how honey bee colonies can efficiently produce mature honey during periods of abundant nectar flow.