Plant molecules make worker bees

The nature of the biological switch that controls whether a female honeybee will become a sterile worker or a sexually active queen has been uncovered by researchers at Nanjing University in China. 

Writing in the journal PLOS Genetics, the team discovered that tiny molecular messages produced in plants, known as microRNAs, end up in the pollen and honey that female bee larvae are fed on as they develop.

This mixture, known as bee bread, is only fed to larvae that grow up to be workers, while potential queens feast on royal jelly, produced by special nurse bees. The plant microRNAs seem to affect the activity of particular genes in the developing workers, including an important gene called TOR which is known to be involved in separating workers from queens.

While it’s long been known that the bees’ dietary differences must have something to do with their sexual development, it wasn’t known exactly how this works. And although microRNAs have been shown to affect the activity of genes, this is the first example of microRNAs made by one species affecting the development of another - so it’s news that has created a bit of a buzz.