The queen of all pheromones

Honey bee queens control their offspring with chemicals (pheromones), but just how these chemicals work largely remained a mystery until recent studies by the "bee team" at Otago's Department of Zoology.

Led by Professor Alison Mercer, the team discovered that exposing young worker bees to queen pheromone alters the chemistry of their brains, with a direct link between these changes in brain biochemistry and complex behaviour.

These findings have the potential to be of specific benefit to the bee industry, Mercer says. They indicate that pheromones produced by the queen bee not only help maintain the colony as a functional unit, but also enhance the survival of the queens themselves.

A component of queen pheromone, homovanillyl alcohol, alters the function of dopamine pathways in young worker bees' brains - levels of dopamine, as well as the levels of dopamine receptor gene expression, are both reduced - and Mercer says the effect on brain function is profound.

A further study then showed that aversive olfactory learning in young worker bees is completely blocked by queen pheromone. Young bees exposed to their mother's pheromone cannot learn to associate odours with a nasty or negative outcome.

Young worker bees perform many essential tasks. Arguably their most important role is to feed and groom the queen, and to distribute her pheromones throughout the colony.

Exposure to their mother's pheromone will prevent young workers from developing an aversion to odours within the hive, including odours produced by the queen herself. So, by blocking aversive learning in young workers, the queen may be making her own life and that of the colony more secure.

One of the biggest challenges in understanding how brains work is working out how brain processes are linked to behaviour, says Mercer.

"We have been able to link events at the cellular and molecular level with changes in the behaviour of the bee. Finding out how queen bees use chemicals to manipulate the behaviour of their offspring is creating a window into understanding the brain of this truly remarkable animal."

FUNDING
Marsden Fund