Odor discrimination and latent inhibition in honeybees

FERNÁNDEZ, VANESA; FARINA WM

Buenos Aires

Congreso; 42º Congreso Internacional de Apicultura Apimondia 2011; 2011

Apimondia

Odor discrimination and latent inhibition in honeybees Fernández, V.M.; Arenas, A.; Farina, W.M.   Grupo de Estudio de Insectos Sociales, Departamento de Biodiversidad y Biología Experimental, IFIBYNE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina. Tel: (+5411) 4576 3445. walter@bg.fcen.uba.ar Animals must learn which of the environmental stimuli predict biologically meaningful events to survive. However, when a stimulus that has been exposed to the surroundings pretends to be associated with reinforcement, it is often difficult to establish a predictive relationship between both stimuli. This phenomenon has been defined as latent inhibition (LI) and was extensively studied in honeybees. We studied the role of volatiles pre-exposed within the hive on appetitive learning considering different ages and sub-castes of the worker bees. Bees were exposed to odors under different conditions and then their learning performances were evaluated at different intervals between the odor-exposure and the differential classical conditioning performed within the proboscis extension response (PER) paradigm. We found that hive-exposed odors offered as a reinforced conditioning stimulus (CS) during acquisition promoted a learning-reduced effect. In contrast, no effect was found when the non-reinforced CS was pre-exposed. Our results showed that this effect varied with the odor identity and it was odor specific. We analyzed the effects of such exposure in individuals of different ages and we did not find differences. In addition we studied the length under different odors’ concentrations and intervals between the exposure and the evaluation. Exposure-conditioning intervals longer than 24h did not show a LI effect unless the odor concentration was increased or exposure was prolonged. Moreover, biogenic amines have been shown to play important roles in learning and memory by modulating states of arousal. For this reason, we studied the aminergic signaling involved in the LI. Our results showed that serotonin might be involved in the LI-signalling. The deferential effects found according to the olfactory exposure characteristics could strongly influence learning abilities and therefore the propagation of chemosensory information among hive mates.