Reputed for their ability to learn and memorise the odours and colours associated with a reward, such as flower nectar, are bees capable of memorising repellent signals?  And in particular, are they endowed with the faculty to learn that a specific odour gives rise to a punishment such as a mild electric shock?  If this is the case, how does their nervous system manage to distinguish repellent stimulations (electric shocks) from appetizing stimulations (nectar)?  It is by studying these questions that the team at the Centre for Research on Animal Cognition (CNRS / University Toulouse 3), headed by Martin Giurfa, has demonstrated that restricted bees (1) learn to associate a specific odour with an electric shock: in the presence of this repellent odour, they extend their sting.  Furthermore, the same bees can remember that another odour is associated with a sweet reward: in this case, they extend their proboscis.  This constitutes the first demonstration of the simultaneous learning by bees of the repellent or attractive nature of certain stimuli.   Following these initial results, the team in Toulouse tried to understand how the "mini-brain" of the bee managed to distinguish between reward and punishment.  It thus established that a biogenic amine (2), octopamine, was activated in the context of a reward, while a different amine, dopamine, was involved in punishment.  This proves the possibility of the simultaneous mastery of two types of associations.  Finally, the distinction between repulsion and attraction appears to be a fundamental principle observed on a major, evolutionary scale, obeying relatively simple neuronal strategies.  This work was published on March 14, 2007 in the journal PLoS ONE.