The method by which queen honeybees control the fertility of worker bees has been identified by New Zealand's Otago University researchers.
It has long been known that worker bees have a limited ability to reproduce in a hive with a queen and brood present, but in their absence, one third will activate their ovaries and lay eggs that hatch into fertile male drones.
What represses the worker bees' fertility is queen pheromone, a secreted chemical substance, but how it achieves this has remained unclear.
Now, Otago genetics researchers have identified that an ancient cell-signalling pathway called Notch, which plays a major role in regulating embryonic development in all animals, has been co-opted to constrain reproduction in worker bees.
The research by Professor Peter Dearden, Dr Elizabeth Duncan and Dr Otto Hyink has been published in the journal Nature Communications.
In it, they have demonstrated that chemically inhibiting Notch signalling can overcome the effect of queen mandibular pheromone (QMP) and promote ovary activity in adult worker bees.
Prof Dearden says they were surprised to find that Notch signalling acts on the earliest stages of egg development in the ovary and that, in the absence of QMP, the Notch receptor in a key region of worker bee ovaries becomes degraded.
"Without active Notch-signalling taking place, the worker bee eggs are now able to mature," he said.
"This contrasts with its role in fruit fly reproduction, in which the signalling is vital for fertility."
Prof Dearden said it wasn't yet clear whether QMP worked directly on ovaries or acted via signalling between the brain and antennae.
"However it is acting, the outcome is that Notch signalling's fundamental role in the ovary has been modified and transformed in honeybees into social control of worker bees reproduction."
