It may still come as a surprise that human beings are not alone in having invented vaccination. Work just published in the Journal of Experimental Biology by Gyan Harwood of the University of Illinois, Urbana-Champaign, confirms that honeybees may invent vaccination earlier.

Being gregarious, honeybees are at constant risk of diseases sweeping through their hives. Most animals which live in crowded conditions have particularly robust immune systems, so it long puzzled entomologists that honeybees do not. Indeed, they actually possess fewer immune-related genes than most solitary bees.

Part of the answer, discovered in 2015, is that queen bees vaccinate their eggs by transferring into them, before they are laid, fragments of proteins from disease-causing pathogens. These act as antigens which trigger the development of a protective immune response in the developing young. But that observation raises the question of how the queen receives her antigen supply in the first place, for she subsists purely on royal jelly, a substance secreted by worker bees which are at the stage of their lives ( which precedes the period that they spend flying around foraging for nectar and pollen ) when they act as nurses to larvae. Dr. Harwood therefore wondered if the nurses were mixing the royal jelly they were producing and fragments from pathogens they had consumed while eating the victuals brought to the hive by the foragers.

Later, the findings suggest that nurse bees are indeed, via their royal jelly, passing antigens on to the queen for inoculation into her eggs. They also mean, because larvae, too, receive royal jelly for the first few days after they hatch, that the nurses are inoculating their larval charges as well. Each infant bee is therefore being vaccinated twice.