Regulation of hemolymph osmolality in feral and domestic honeybees, Apis mellifera L. (Hymenoptera: Apidae)

Experiments were conducted to compare the ability of unmanaged fetal and managed domestic honeybees in the arid Southwest to regulate hemolymph solutes, osmolality, and uric acid. Honeybees from feral and domestic colonies were desiccated (at 30°C and 0% humidity) for 2 h with undesiccated bees held as controls. Hemolymph osmolality, proteins, amino acid, and uric acid concentrations were analyzed. Hemolymph osmotic pressures of desiccated feral bees were significantly lower than those of domestic honeybees (P < 0.004). There was a significant difference in hemolymph protein concentrations between undesiccated and desiccated honeybees (P < 0.001). The hemolymph concentration of amino acids was significantly higher in undesiccated bees than in desiccated honeybees (P < 0.0031). There were no differences in uric acid concentrations between feral and domestic bees, and between desiccated and undesiccated honeybees. Hence, differences in temperature tolerance and water balance between feral and domestic honey bees are not explained by differential regulation of hemolymph osmolality, proteins, or free amino acids, or by regulation of uric acid excretion.