Anja Buttstedt

Western honey bee (Apis mellifera) larvae are by no means fed with honey or pollen directly but with a jelly-like substance which provides all the nutrients that the larvae need to develop into adult honey bees. This food jelly is a product of two specialized head glands of brood-raising worker bees. The hypopharyngeal gland secretion contributes proteins to food jelly and the secretion of the mandibular glands contains amongst others fatty acids and sterols, mainly 24-methylenecholesterol (24MC). The main proteins of food jelly are members of the major royal jelly protein (mrjp) gene family, that is spread throughout but limited to the insect order Hymenoptera, as well as apisimin, an orphan gene in the genus Apis. MRJP1 and apisimin form together with the sterol 24MC a protein-sterol complex which forms fibrillar structures in the acidic environment of food jelly (pH 4.0) thereby increasing viscosity. This viscosity increase of the food jelly is crucially important for honey bee queen larvae which are raised in a special queen cell at the lower edge of the wax comb. The queen larva literally hangs in the cell that is open at the bottom and is glued to the cell ceiling by its food jelly. Thus, food jelly does not only nourish the queen larva but also prevents her from falling out of the cell and thus ensures the survival of the entire colony.
Whereas food jelly that is fed to queen larvae, royal jelly, is somewhat studied, our knowledge on food jelly fed to workers and drones has hardly increased since the 19th century. Thus, my future research will concentrate more on worker and drone jelly. I will elucidate which functions MRJPs, apisimin and 24MC have in these food jellies and to what extent the proteins play a role in sterol provisioning of all honey bee larvae.