Bumblebees produce a signalling pheromone from tergal glands located on their dorsal abdomen as discovered in experiments performed by A. Dornhaus, A. Brockmann and L. Chittka in 2003. They monitored the activity of bee colonies after exposure to products from several glands located along the bee's body. The only one yielding significant changes in activity level came from the tergites VI and VII. This is similar to a pheromone produced from the Nasanov gland in honeybees, but differs in the active compound. It has been suggested that this pheromone may facilitate learning of floral scents, since its release is coupled with the import of the floral scent from the nectar collected by the successful forager. Experiments by Molet, Chittka and Raine in 2009 showed that bumblebees may be able to learn floral scents associated with rewarding flowers better if the particular scent is found in nectar deposited in the honeypots.