It's no coincidence that hives are a byword for industry; female worker bees scurry around tending to their queen, yet male drones hardly seem to contribute at all, their existence is geared solely to mating with the queen. Jean-Christophe Sandoz, from the Université Paul Sabatier in Toulouse,France, explains that apart from their different social roles, the male drone's olfactory processing antennal lobe is quite different from the female's; four of the drone's odour-sensitive glomeruli are enlarged relative to the ordinary glomeruli, and it had been suggested, but never proved, that they were responsible for the male's sensitivity to the queen's pheromones.

Curious to know how the antennal lobe responds to everyday hive odours(p. 3587), Sandoz used calcium imaging to visualise the activity of glomeruli on the antennal lobe's surface in response to various scents. Testing the effects of several queen pheromone components, Sandoz found that main constituent, 9-ODA,triggered a response in the enlarged MG2 glomerulous only; MG2 responds specifically to the queen's pheromone. Sandoz suggests that `most, if not all,of the olfactory sensory neurones tuned to [the queen pheromone component]9-ODA project to this macroglomerulus'.

Sandoz, J.-C. (
). Odour-evoked responses to queen pheromone components and to plant odours using optical imaging in the antennal lobe of the honey bee drone Apis mellifera L.
J. Exp. Biol.