Scientists discover why Royal Jelly creates Queens

RESEARCHERS believe they have found why royal jelly - secreted by adult nurse bees - cause honeybee larvae to develop into queen bees.

Royal jelly is a food substance secreted by adult bees that is fed in some measure to all young bees. The larvae that are chosen to be queens are fed an exclusive diet of royal jelly.

A copious diet of royal jelly flicks a genetic switch in young bees and causes them to develop into a queen bee, by boosting the activity of particular genes, say Australian researchers. They say the findings could provide clues on how the environment interacts with genes to produce obesity, longevity, sterility and brain disorders in humans.

Molecular biologist Dr Ryszard Maleszka and colleagues from the Australian National University in Canberra report their findings today in the journal Science.

"The larvae that develop into workers and queens are genetically identical," says Maleszka.

Yet he says those fattened up on royal jelly become fertile queen bees and are much larger and longer-lived than the rest that turn into sterile workers.

The researchers wanted to test the idea that royal jelly controls queen and worker development via epigenetics. Epigenetics involves chemical modification of the genome to change gene expression, and provides a way for the environment to affect an organism's genetics.

Some scientists think epigenetic factors explain why psychiatric diseases such as schizophrenia don't always appear in both identical twins.

"When we silenced a gene controlling DNA methylation without recourse to royal jelly, we discovered that the larvae began to develop as queens with the associated fertility, rather than as infertile workers," researcher Ryszard Maleszka said.

Dr Maleszka and his colleagues believe this is the first time that DNA methylation - a molecular process common in vertebrates, including humans - has been functionally implicated in insects.

They suspect the process could also be responsible for how the insects' brains develop, and therefore be connected to bee behaviour.

When the Dnmt3 gene was silenced, most of the larvae turned into queens. When the Dnmt3 gene was active, most of the larvae turned into workers.

"It was a beautiful switch," says Maleszka. "The results were so spectacular."

Maleszka says he doesn't know how royal jelly silences the Dnmt3 gene but speculates the insulin signalling pathway is involved.

A spin-off from the new work is that the team has developed a way of producing queen bees in a test tube, without using royal jelly. Maleszka says this is of great interest to US beekeepers who want to get "clean" queen bees to help re-establish colonies devastated by Colony Collapse Disorder.