THE OLFACTORY MEMORY OF THE HONEYBEE APIS-MELLIFERA .2. BLOCKING BETWEEN ODORANTS IN BINARY-MIXTURES

Proboscis extension conditioning of honeybee workers was used to study the processing of odorants when bees were conditioned to binary mixtu res. Responses to a set of pure floral odors and pheromones after cond itioning have already been described. When bees are conditioned to cer tain mixtures of odorants, the response to both components is equal to that when they are tested alone. However, mixtures of an aliphatic al dehyde and an alcohol elicit asymmetric response patterns; that is, th e response to the aldehyde is much stronger than that to the alcohol. A bee's response to the alcohol after it had been trained in an aldehy de background is significantly lower than when the bee is trained to r espond to the same alcohol in the background of another odorant. Such response patterns are not necessarily caused by a behavioral decrement resulting from a compound-unique perceptual effect produced by the mi xture. Furthermore, studies of blocking show that behavioral acquisiti on in response to one component can be hindered or blocked by pretrain ing with the other component. These results suggest that honeybees can perceive the individual components of some binary mixtures. The simil arities in neural processing in olfactory systems of vertebrates and i nvertebrates mean that such studies could elucidate behavioral mechani sms of olfaction in a wide phylogenetic spectrum of animals.