A new study has found that queen bees vaccinate their young naturally — an incredible feat that scientists are trying to fully understand.

The study, published in the journal PLOS Pathogens, could potentially allow scientists to replicate such a process and therefore further boost the immunity of bees, which have been under threat and are a vital part of our agricultural system, according to a Discovery News report.

Scientists had no idea how bees transferred immunity to their offspring until the study took a close look at the issue, said Gro Amdam of Arizona State University according to the report. Amdam co-authored the study.

The study takes advantage of 15 years of basic research on vitellogenin, and it has taken scientists that long to crack the code.

Apparently, in honeybee colonies the queen doesn’t leave the nest, meaning that bees must bring food to her, so they go off and look for pollen and nectar. But when they do so, they also pick up some unwelcome passengers: pathogens. All of this is mixed into one jelly-like substance for the queen to eat.

The bacteria then gets inside the queen bee’s gut, where it is stored in a liver-like organ. The bacteria then binds to protein called vitellogenin, which is then sent to the blood to developing eggs, creating a natural inoculation for bee babies.

This simple vaccine is why bees are able to avoid the deadly diseases out in the world.

But now bees face a different threat: humans, particularly the widespread use of pesticides. Now that scientists better understand vitellogenin, they might be able to work on an edible, natural vaccine that could protect bees.